What are enzyme assays and why are they important in laboratory settings?

Enzyme assays are laboratory methods specifically designed to measure the activity of enzymes. They are crucial tools for researchers studying enzyme kinetics, which is the rate at which enzymes catalyze reactions, and enzyme inhibition, which involves substances that slow down or block enzyme activity.

How can the amount or concentration of an enzyme be quantified?

The quantity or concentration of an enzyme can be expressed in two primary ways: as molar amounts, similar to any other chemical substance, or in terms of its activity using specific enzyme units.

What does enzyme activity measure, and what conditions influence it?

Enzyme activity serves as a measure of the quantity of active enzyme present in a sample. This activity is dependent on various physical conditions, such as temperature, pH, and substrate concentration, which must be specified when reporting enzyme activity.

What is the formula provided for calculating enzyme activity?

The formula provided for calculating enzyme activity is a = n_t = r × V. This formula relates enzyme activity (a) to the moles of substrate converted per unit time (n_t), the reaction rate (r), and the reaction volume (V).

What are the components of the enzyme activity formula: a = n_t = r × V?

In the formula a = n_t = r × V: 'a' represents the Enzyme activity. 'n_t' represents the Moles of substrate converted per unit time. 'r' represents the Rate of the reaction. 'V' represents the Reaction volume.

What is the standard international (SI) unit for enzyme activity, and why is it often not practical?

The SI unit for enzyme activity is the katal (symbol: kat), defined as one mole of substrate converted per second (mol s⁻¹). However, this unit is considered excessively large for most practical laboratory measurements.

What is the more commonly used unit for enzyme activity, and what does it represent?

A more practical and widely used unit for enzyme activity is the enzyme unit (U). One enzyme unit is defined as the amount of enzyme that catalyzes the conversion of one micromole (μmol) of substrate per minute (min⁻¹).

How can enzyme activity be measured using standardized substrates like gelatin or milk proteins?

Enzyme activity can also be quantified using standardized substrates, yielding units such as Gelatin Digesting Units (GDU) or Milk Clotting Units (MCU). These units measure how quickly a specific amount of enzyme can digest gelatin or clot milk proteins, respectively.

What is the approximate relationship between Gelatin Digesting Units (GDU) and Milk Clotting Units (MCU)?

One Gelatin Digesting Unit (GDU) is approximately equivalent to 1.5 Milk Clotting Units (MCU).

How does substrate concentration typically influence the rate of an enzyme-catalyzed reaction?

Generally, increasing the concentration of the substrate will increase the rate of an enzyme-catalyzed reaction, as there are more substrate molecules available to bind with the enzyme's active sites.

Why does the reaction rate of an enzyme-catalyzed reaction eventually level out, even with increasing substrate concentration?

The reaction rate levels out at higher substrate concentrations because the enzyme becomes saturated. This means that the active sites of all available enzyme molecules are occupied by substrate molecules most of the time, and the enzyme cannot process substrate any faster, regardless of additional substrate availability.

What is meant by the 'specific activity' of an enzyme?

Specific activity is a common unit used to measure enzyme purity. It is defined as the enzyme's activity per milligram of total protein in a sample, typically expressed in micromoles of product formed per minute per milligram of protein (μmol min⁻¹ mg⁻¹).

How is specific activity calculated?

Specific activity is calculated by multiplying the rate of the reaction by the reaction volume and then dividing the result by the mass of the total protein present in the sample.

What are the SI and practical units for specific activity?

The SI unit for specific activity is katal per kilogram (kat/kg), but a more practical and commonly used unit is micromoles per milligram per minute (μmol/(mg*min)).

What does enzyme processivity refer to, and how is it related to specific activity?

Enzyme processivity refers to the capability of an enzyme to perform its catalytic function repeatedly without dissociating from its substrate or product. Specific activity, usually measured at saturating substrate concentrations, is generally constant for a pure enzyme and can be an indicator of this processivity.

What is active site titration, and what is its purpose in enzyme analysis?

Active site titration is a process used to determine the exact amount of active enzyme present in a sample. It helps eliminate errors that might arise from variations in enzyme preparation, such as misfolded enzymes or different cultivation batches, by quantifying the number of functional active sites, often using an irreversible inhibitor.

How can the turnover number be determined from specific activity?

If the molecular weight of the enzyme is known, the turnover number can be calculated from the specific activity. The turnover number represents the number of substrate molecules converted per active enzyme molecule per unit time (often per second).

How is the rate of a chemical reaction defined in biochemical terms?

The rate of a chemical reaction is defined as the change in concentration of a substrate disappearing or a product being produced over a specific period of time, typically measured in moles per liter per second (mol L⁻¹ s⁻¹).

How can the percentage purity of an enzyme sample be determined?

The percentage purity of an enzyme sample can be calculated by comparing its specific activity to the specific activity of a known pure enzyme. The formula is: % purity = 100% × (specific activity of enzyme sample / specific activity of pure enzyme). An impure sample will exhibit lower specific activity because a portion of its mass is not the active enzyme.

What fundamental principle do all enzyme assays rely on for measurement?

All enzyme assays fundamentally rely on measuring either the consumption of a substrate or the production of a product over a period of time. Various methods exist to quantify these changes.

What are the four main types of experimental approaches used in enzyme kinetics studies?

The four main types of experiments used to study enzyme-catalyzed reactions are: initial rate experiments, progress curve experiments, transient kinetics experiments, and relaxation experiments.

Describe the characteristics and advantages of initial rate experiments in enzyme kinetics.

Initial rate experiments involve mixing an enzyme with a large excess of substrate. After a brief initial transient phase, the reaction reaches a steady state where substrate concentration remains approximately constant. Rates are measured during this steady state, typically by monitoring product accumulation over a short time. These experiments are favored because they are relatively simple to perform and analyze, minimizing complications like back-reactions or enzyme degradation.

What are progress curve experiments in enzyme kinetics?

Progress curve experiments involve monitoring the concentration of substrate or product over a longer period, extending beyond the initial transient phase until the reaction approaches equilibrium. Kinetic parameters are determined from the mathematical expressions describing how concentrations change over time.

What are transient kinetics experiments, and why are they more challenging?

Transient kinetics experiments focus on tracking the reaction's behavior during the initial, rapid phase as it transitions from the start to the steady-state kinetics period. These experiments are more difficult because they require specialized techniques like flash photolysis or rapid mixing methods (e.g., stopped-flow, quenched flow) to capture very fast events.

Explain the principle behind relaxation experiments in enzyme kinetics.

Relaxation experiments involve perturbing a reaction mixture already at equilibrium, for example, by a sudden change in temperature, pressure, or pH. The experiment then monitors how the system returns to equilibrium. These experiments analyze the reversible nature of the reaction.

What are the limitations of relaxation experiments for determining enzyme mechanisms?

While useful for studying reaction dynamics, relaxation experiments are generally less sensitive to specific mechanistic details and are therefore not typically the primary method for identifying the precise mechanism of an enzyme reaction, although they can provide some mechanistic insights under certain conditions.

How are enzyme assays broadly categorized based on their sampling methods?

Enzyme assays can be divided into two main categories based on how samples are handled: continuous assays, which provide ongoing measurements of activity, and discontinuous assays, which involve taking samples at intervals, stopping the reaction within those samples, and then measuring substrate or product concentrations.

What makes continuous assays particularly convenient for researchers?

Continuous assays are convenient because they provide a real-time, uninterrupted reading of enzyme activity, eliminating the need for additional sample processing steps to determine the reaction rate.

How do spectrophotometric assays measure enzyme activity?

Spectrophotometric assays monitor the progress of an enzyme reaction by measuring changes in the amount of light absorbed by the assay solution. If the change in absorbance occurs in the visible light spectrum, the assay is often referred to as a colorimetric assay.

What is a colorimetric assay, and can you give an example?

A colorimetric assay is a type of spectrophotometric assay where a change in the color of the solution, due to a change in light absorption in the visible spectrum, is measured. The MTT assay, which uses a tetrazolium dye, is an example of a colorimetric assay.

Why is UV light frequently utilized in spectrophotometric enzyme assays?

UV light is often used because common coenzymes like NADH and NADPH absorb UV light strongly when they are in their reduced form but absorb very little when they are in their oxidized form. This difference allows for sensitive monitoring of reactions involving these coenzymes.

How can an oxidoreductase enzyme that uses NADH be assayed using UV spectrophotometry?

An oxidoreductase enzyme utilizing NADH can be assayed by monitoring the decrease in UV absorbance at a wavelength of 340 nm. As the enzyme consumes NADH during the reaction, the absorbance at this specific wavelength decreases, providing a measurable signal of enzyme activity.

What is a coupled assay in enzyme analysis?

A coupled assay is a technique used when the primary enzyme reaction doesn't directly produce a measurable change in absorbance or fluorescence. In a coupled assay, the product of the enzyme reaction being studied is used as the substrate for a second, easily detectable indicator reaction.

Provide an example of a coupled assay.

A common example is the coupled assay for hexokinase. The glucose-6-phosphate produced by hexokinase is then used as a substrate by the enzyme glucose-6-phosphate dehydrogenase. This second enzyme's reaction produces NADPH, which has a distinct UV absorbance, allowing the activity of hexokinase to be indirectly measured.

How do fluorometric assays measure enzyme activity?

Fluorometric assays measure enzyme activity by detecting differences in fluorescence between the substrate and the product. Fluorescence occurs when a molecule absorbs light at one wavelength and emits light at another, longer wavelength.

What are the advantages and potential disadvantages of fluorometric assays compared to spectrophotometric assays?

Fluorometric assays are generally much more sensitive than spectrophotometric assays. However, they can be susceptible to interference from impurities in the sample and may be affected by the instability of fluorescent compounds when exposed to light.

How can the reduced forms of NADH and NADPH be utilized in fluorometric enzyme assays?

The reduced forms of NADH and NADPH are fluorescent, while their oxidized forms are not. Therefore, oxidation reactions involving these coenzymes can be monitored by observing a decrease in fluorescence, and reduction reactions by observing an increase in fluorescence.

What are calorimetric assays, and what makes them versatile?

Calorimetric assays measure the heat released (exothermic) or absorbed (endothermic) during chemical reactions. They are considered very versatile because many reactions involve a heat change, and with sensitive instruments like microcalorimeters, only small amounts of enzyme and substrate are needed. Calorimetry can even be used to assay reactions that are difficult or impossible to measure by other methods.

What is chemiluminescence, and how is it applied in enzyme assays?

Chemiluminescence is the emission of light as a result of a chemical reaction. Some enzyme reactions directly produce light, which can be measured to quantify product formation. This method can be extremely sensitive, allowing detection over long periods, but quantification can be challenging as not all emitted light may be captured.

Provide examples of enzyme detection methods that utilize chemiluminescence.

Horseradish peroxidase is often detected using enzymatic chemiluminescence (ECL), a common technique in western blotting. Another example is the enzyme luciferase, found in fireflies, which naturally produces light by converting its substrate, luciferin.

What does static light scattering measure in the context of macromolecules?

Static light scattering measures the product of the weight-averaged molar mass and the concentration of macromolecules in a solution. When the total concentration of species remains constant, changes in the scattering signal directly indicate variations in the weight-averaged molar mass, often due to complex formation or dissociation.

What is Microscale Thermophoresis (MST), and how can it be used to measure enzymatic activity?

Microscale Thermophoresis (MST) is a technique that measures the movement of molecules along a temperature gradient. In enzyme assays, the thermophoretic behavior of a fluorescently labeled substrate changes significantly when it is modified by an enzyme, allowing for the real-time measurement of enzymatic activity and inhibition constants with high time resolution.

What are the advantages of using MST for enzyme analysis?

MST requires very small sample volumes (e.g., 5 μL) and low enzyme concentrations (e.g., 10 nM). It also allows for multiplexing, where two different substrates labeled with distinct fluorophores can be monitored simultaneously, enabling experiments like substrate competition studies.

What characterizes discontinuous assays in enzyme analysis?

Discontinuous assays involve taking samples from the reaction mixture at specific time intervals. The enzyme reaction within each collected sample is then stopped, and the concentration of substrate or product is measured afterward.

How do radiometric assays function, and what isotopes are commonly used?

Radiometric assays measure enzyme activity by tracking the incorporation of radioactivity into substrates or the release of radioactivity from substrates. Commonly used radioactive isotopes include Carbon-14 (¹⁴C), Phosphorus-32 (³²P), Sulfur-35 (³⁵S), and Iodine-125 (¹²⁵I).

What makes radiometric assays particularly sensitive and specific?

Radiometric assays are highly sensitive and specific because radioactive isotopes allow for the precise labeling of individual atoms within a substrate molecule. This enables the detection and quantification of even very small amounts of reaction product, often making them the only viable method for measuring specific reactions within complex biological mixtures like crude cell extracts.

How are products typically measured in radiometric assays?

Radioactivity in samples from radiometric assays is usually measured using a scintillation counter, a device designed to detect and quantify the light flashes (scintillations) produced when radioactive decay interacts with a scintillator material.

What chromatographic techniques are commonly employed in enzyme assays?

Chromatographic assays often use high-performance liquid chromatography (HPLC) to separate the components of a reaction mixture. Simpler techniques like thin-layer chromatography (TLC) can also be used. Advancements like ultra-high pressure liquid chromatography (UHPLC) further enhance sensitivity and speed.

How can the sensitivity of chromatographic enzyme assays be improved?

The sensitivity of chromatographic assays can be increased by labeling the substrates or products with radioactive or fluorescent tags. Additionally, using more advanced chromatographic instruments, such as UHPLC systems that operate at higher pressures, can also improve sensitivity and resolution.

What is the general effect of salt concentration on most enzymes?

Most enzymes function optimally within a specific range of salt concentrations, typically between 1-500 mM. Extremely high salt concentrations can interfere with the weak ionic bonds that maintain the protein's structure, potentially leading to reduced activity or denaturation.

How does temperature influence enzyme activity and reaction rates?

Increasing temperature generally increases the rate of enzyme-catalyzed reactions up to a certain point. Beyond this optimal range, higher temperatures cause the enzyme's protein structure to denature, leading to a sharp decrease in reaction rate. Enzymes from organisms living in extreme environments, like thermophilic archaea, can remain stable at much higher temperatures.

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Enzyme Units

Measuring Enzyme Concentration

While enzymes, like any chemical substance, can be quantified in molar amounts, their concentration is often expressed in terms of enzyme units, which directly relate to their catalytic activity. This approach is fundamental for understanding enzyme kinetics and inhibition.

Defining Enzyme Activity

Enzyme activity is a quantitative measure of the amount of active enzyme present. It is inherently dependent on specific physical conditions, such as temperature, pH, and substrate concentration, which must always be clearly specified when reporting activity values.

The fundamental relationship is expressed as:

\mathrm {a} =\mathrm {n} _{\text{t}}=\mathrm {r} \times \mathrm {V}

Where:

$\mathrm {a}$ = Enzyme activity
$\mathrm {n} _{\text{t}}$ = Moles of substrate converted per unit time
$\mathrm {r}$ = Rate of the reaction
$\mathrm {V}$ = Reaction volume

Standard Units of Measurement

The International System of Units (SI) defines the katal (kat) as the unit of enzyme activity, equivalent to one mole per second (mol·s^-1). However, this unit is often impractically large for typical laboratory measurements.

A more commonly employed unit is the Enzyme Unit (U), defined as micromoles of substrate converted per minute (µmol·min^-1). Note that 1 U is approximately equal to 16.67 nanokatal (nkat).

Specialized units exist for specific enzymes or substrates, such as gelatin digesting units (GDU) and milk clotting units (MCU), which quantify the enzyme's ability to break down gelatin or clot milk, respectively.

Enzyme Activity

Rate and Substrate Concentration

The rate of an enzyme-catalyzed reaction generally increases with substrate concentration. However, this increase is not linear indefinitely. As substrate concentration rises, the enzyme's active sites become increasingly occupied. Eventually, the enzyme reaches saturation, where the rate plateaus because all active sites are consistently engaged, and the rate becomes maximal (V_max).

Temperature Effects

Temperature significantly influences enzyme activity. Initially, increasing temperature accelerates the reaction rate due to increased molecular motion. However, beyond an optimal temperature, activity sharply declines. This is because excessive heat disrupts the delicate tertiary structure of the enzyme, denaturing the active site through the breakdown of ionic and hydrogen bonds.

For most human enzymes, the optimum temperature range is typically between 35-40°C. Enzymes from thermophilic organisms, adapted to extreme heat, can remain stable and active at temperatures up to 100°C.

pH Sensitivity

Enzymes exhibit distinct pH optima for activity. Deviations from this optimum, either acidic or alkaline, can alter the ionization state of amino acid residues within the enzyme, particularly at the active site. This can disrupt substrate binding and catalysis, and at extreme pH values, can lead to denaturation and irreversible loss of function.

While many enzymes function optimally between pH 6 and 8, exceptions exist, such as pepsin (active in the highly acidic environment of the stomach, pH ~2) and trypsin (optimal around pH 8).

Specific Activity

Measuring Enzyme Purity

Specific activity is a critical metric defined as the enzyme activity per unit mass of total protein (typically expressed in µmol·min^-1·mg^-1). It serves as a quantitative measure of enzyme purity in a preparation.

A higher specific activity indicates a greater proportion of the total protein mass is the active enzyme of interest.

Turnover Number

When the molecular weight of a pure enzyme is known, specific activity can be used to calculate the turnover number. This value represents the number of substrate molecules converted to product by a single enzyme molecule per unit time (often per second). It is a direct measure of the enzyme's catalytic efficiency.

Active Site Titration

To ensure accurate measurements, especially when dealing with variations in enzyme batches or potential misfolding, active site titration can be employed. This involves using an irreversible inhibitor to quantify the number of active enzyme molecules present. The specific activity is then calculated based on this precise count of active enzyme, yielding a more reliable measure of catalytic potential.

Related Terminology

Reaction Rate

The rate of a reaction quantifies the change in concentration of a substrate disappearing or a product appearing over a specific period. It is typically measured in molar units per second (mol·L^-1·s^-1).

Percentage Purity

The percentage purity of an enzyme preparation can be estimated by comparing its specific activity to that of the pure enzyme. The formula is:

% Purity = 100% × (Specific Activity of Sample / Specific Activity of Pure Enzyme)

An impure sample will exhibit a lower specific activity due to the presence of non-enzymatic protein mass.

Equilibrium and Kinetics

While enzyme assays primarily focus on reaction rates under specific conditions, understanding the overall reaction equilibrium is also important. However, the focus is typically on the initial rates, especially when enzyme degradation or product inhibition is minimal, simplifying kinetic analysis.

Types of Assays

Core Principle

All enzyme assays fundamentally measure either the depletion of substrate or the accumulation of product over time. The diversity of enzyme assays arises from the wide array of techniques available for accurately detecting and quantifying these molecular changes.

Experimental Approaches

Biochemists commonly employ four experimental paradigms:

Initial Rate Experiments: Measure reaction velocity under conditions where substrate concentration is high and remains relatively constant, simplifying analysis.
Progress Curve Experiments: Track substrate or product concentration over extended periods, allowing analysis as the reaction approaches equilibrium.
Transient Kinetics Experiments: Investigate the very rapid initial phase of the reaction before steady-state is reached, requiring specialized equipment like stopped-flow apparatus.
Relaxation Experiments: Perturb an equilibrium mixture (e.g., with a temperature jump) and monitor the return to equilibrium, providing information about the reaction mechanism.

Sampling Methods

Enzyme assays can be broadly categorized based on how samples are handled:

Continuous Assays: Provide real-time monitoring of the reaction progress, offering immediate data on reaction rates.
Discontinuous Assays: Involve taking discrete samples at intervals, stopping the reaction within each sample, and then measuring substrate or product concentrations.

Continuous Assays

Spectrophotometric Methods

These assays monitor changes in light absorbance, typically in the visible (colorimetric) or ultraviolet (UV) range. A common example involves tracking the absorbance change associated with the oxidation or reduction of coenzymes like NADH or NADPH at 340 nm.

Coupled Assays

When a primary enzyme reaction doesn't produce a directly measurable signal (e.g., change in absorbance), a coupled assay can be employed. This involves linking the primary reaction to a secondary, easily detectable reaction. For instance, hexokinase activity can be assayed by coupling the production of glucose-6-phosphate to the reduction of NADP+ to NADPH, catalyzed by glucose-6-phosphate dehydrogenase.

Fluorometric Methods

These assays detect changes in fluorescence, offering significantly higher sensitivity than spectrophotometric methods. They measure the difference in fluorescence between substrate and product. For example, the oxidation of fluorescent NADH to non-fluorescent NAD+ can be monitored. Synthetic substrates that release fluorescent dyes upon enzymatic cleavage are also widely used.

Calorimetric & Chemiluminescent Assays

Calorimetric assays measure the heat released or absorbed during a reaction, applicable even when other detection methods fail. Chemiluminescent assays detect the light produced by a chemical reaction, offering extreme sensitivity, though quantification can be challenging. A notable example is the use of luciferase enzymes found in fireflies.

Light Scattering & MST

Light scattering assays measure changes in light scattering by macromolecules in solution, allowing quantification of complex formation stoichiometry and kinetics. Microscale Thermophoresis (MST) monitors the movement of molecules in a temperature gradient. Changes in this movement upon enzymatic modification of a labeled substrate provide real-time kinetic data with minimal sample consumption.

Discontinuous Assays

Radiometric Assays

These highly sensitive and specific assays utilize radioactive isotopes (e.g., ¹⁴C, ³²P, ³⁵S) to label substrates or products. Radioactivity is measured using a scintillation counter. They are particularly useful for analyzing complex biological mixtures like cell lysates.

Chromatographic Methods

Product formation or substrate consumption is measured after separating the reaction components using chromatography, most commonly High-Performance Liquid Chromatography (HPLC). Advanced techniques like Ultra-High-Performance Liquid Chromatography (UHPLC) can further enhance sensitivity and speed.

Factors Affecting Assays

Salt Concentration

Most enzymes function optimally within a specific range of salt concentrations (typically 1-500 mM). High salt levels can interfere with the ionic interactions crucial for protein structure and function, potentially leading to denaturation. Halophilic organisms possess enzymes adapted to high salt environments.

Temperature Influence

As discussed, temperature affects both reaction rate and enzyme stability. The observed rate is a product of the catalytic rate and the denaturation rate. Assays must be conducted under controlled temperature conditions relevant to the enzyme's physiological environment or specific experimental goals.

pH Effects

Enzyme activity is highly sensitive to pH. Each enzyme has an optimal pH range. Extreme pH values can alter the enzyme's three-dimensional structure and the ionization state of critical residues, leading to denaturation and loss of function. Maintaining the correct pH buffer is essential for accurate assays.

Enzyme Saturation

When substrate concentration is significantly increased, the enzyme active sites become saturated. At this point, the reaction rate reaches its maximum (V_max) and is no longer dependent on further increases in substrate concentration. Assays are often performed under saturating substrate conditions to measure V_max.

Macromolecular Crowding

In concentrated biological solutions, the high density of macromolecules can alter reaction rates and equilibrium constants. This phenomenon, known as macromolecular crowding, can significantly impact enzyme behavior compared to dilute experimental conditions.

Notable Assays

Common Assays

Several established assay methods are frequently used in biochemical research:

MTT Assay (Cell viability/metabolic activity)
Fluorescein Diacetate Hydrolysis (Esterase activity)
p-Nitrophenylphosphate Assay (Phosphatase activity)

Related Concepts

Foundational Topics

Understanding enzyme assays is closely linked to several core biochemical concepts:

Enzyme Kinetics
Enzyme Inhibitors
Enzyme Units
Assay Methodologies
Protein Stability

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References

A full list of references for this article are available at the Enzyme assay Wikipedia page

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This page was generated by an Artificial Intelligence and is intended for informational and educational purposes only. The content is derived from publicly available data and may not be exhaustive or entirely up-to-date.

This is not professional scientific advice. The information provided herein is not a substitute for expert consultation in biochemistry, enzymology, or related fields. Always consult with qualified professionals and refer to primary literature for specific applications and interpretations.

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Enzyme Assays: Quantifying Biological Catalysis

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Enzyme Units 🔢

🔬 Measuring Enzyme Concentration

⚙️ Defining Enzyme Activity

⚖️ Standard Units of Measurement

Enzyme Activity 📊

📈 Rate and Substrate Concentration

🌡️ Temperature Effects

🧪 pH Sensitivity

Specific Activity ✨

purity Measuring Enzyme Purity

🔄 Turnover Number

🎯 Active Site Titration

Related Terminology 📚

⏱️ Reaction Rate

💯 Percentage Purity

⚖️ Equilibrium and Kinetics

Types of Assays 🔬

⏱️ Core Principle

🔄 Experimental Approaches

📊 Sampling Methods

Continuous Assays ▶️

💡 Spectrophotometric Methods

🔗 Coupled Assays

🌟 Fluorometric Methods

🔥 Calorimetric & Chemiluminescent Assays

✨ Light Scattering & MST

Discontinuous Assays ⏳

☢️ Radiometric Assays

chromatography Chromatographic Methods

Factors Affecting Assays ⚙️

🧂 Salt Concentration

🌡️ Temperature Influence

💧 pH Effects

⬆️ Enzyme Saturation

👥 Macromolecular Crowding

Notable Assays 📋

✅ Common Assays

Related Concepts 🔗

🧬 Foundational Topics

Teacher's Corner 🧑‍🏫

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📜 References

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📜 Important Notice

Dive in with Flashcard Learning!

Enzyme Units

Measuring Enzyme Concentration

Defining Enzyme Activity

Standard Units of Measurement

Enzyme Activity

Rate and Substrate Concentration

Temperature Effects

pH Sensitivity

Specific Activity

Measuring Enzyme Purity

Turnover Number

Active Site Titration

Related Terminology

Reaction Rate

Percentage Purity

Equilibrium and Kinetics

Types of Assays

Core Principle

Experimental Approaches

Sampling Methods

Continuous Assays

Spectrophotometric Methods

Coupled Assays

Fluorometric Methods

Calorimetric & Chemiluminescent Assays

Light Scattering & MST

Discontinuous Assays

Radiometric Assays

Chromatographic Methods

Factors Affecting Assays

Salt Concentration

Temperature Influence

pH Effects

Enzyme Saturation

Macromolecular Crowding

Notable Assays

Common Assays

Related Concepts

Foundational Topics

Teacher's Corner

True or False?

Test Your Knowledge!

Gamer's Corner

Discover other topics to study!

References

Feedback & Support

Disclaimer

Important Notice