# What is protein specific activity?

## What is protein specific activity?

Specific activity It is the micro moles of product formed by an enzyme in a given amount of time (minutes) under given conditions per milligram of total proteins. Specific activity is equal to the rate of reaction multiplied by the volume of reaction divided by the mass of total protein.

What is enzyme activity and specific activity?

The key difference between enzyme activity and specific activity is that the enzyme activity refers to the amount of substrates converted to products per unit time while the specific activity of an enzyme refers to the activity of an enzyme per milligram of protein. Most enzymes are protein molecules.

### How do you calculate specific activity?

In summary, specific activity = enzyme units / (vol. in µl x (protein conc. in mg per ml / 1000))

What is the best definition of active site?

In biology, the active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction. The active site consists of amino acid residues that form temporary bonds with the substrate (binding site) and residues that catalyse a reaction of that substrate (catalytic site).

## What does specific activity indicate?

The specific activity indicates how much of the total protein is the enzyme we try to isolate; therefore, its value should increase as the purification progresses.

What is the difference between specific activity and total activity?

Total activity is measured by the enzymatic activity in the volume of fraction used in the assay multiplied by the fraction’s total volume. Specific activity is the total activity divided by total protein. The yield is the amount of activity retained after each purification step.

### What is meant by specific activity?

Specific activity is the activity per quantity of a radionuclide and is a physical property of that radionuclide. Activity is a quantity (for which the SI unit is the becquerel) related to radioactivity. Thus, specific activity is defined as the activity per quantity of atoms of a particular radionuclide.

What is specific activity used for during protein purification?

Specific activity is the ratio of activity units to amount of protein (U/mg), which should increase during the purification. During the purification process, lots of undesired proteins are purified away, but the desired protein giving the activity remains, thereby becoming enriched at each step.

## How do you find the specific activity of a protein?

Specific enzyme activity (usually stated simply as ‘specific activity’) is the number of enzyme units per ml divided by the concentration of protein in mg/ml. Specific activity values are therefore quoted as units/mg or nmol/min/mg (if unit definition B is applied).

What is meant by enzyme specificity?

Enzymes are specific because different enzymes have differently shaped active sites. The shape of the active site of an enzyme is complementary to the shape of its specific substrate . This means they are the correct shapes to fit together. Temperature has an effect on enzyme activity.

### Why is the active site specific for a particular substrate?

The active site is a groove or pocket formed by the folding pattern of the protein.. This together with the chemical properties of the amino acids and co – factors permits only a particular substrate to bind to the site, thus rendering it specific only to certain proteins.

Why is it important useful to measure specific activity?

Specific activity is an important measure of enzyme purity and values for different batches of a pure enzyme should be the same, within normal experimental error. Batches that are below the expected specific activity value may contain impurities or enzyme molecules that have become denatured.

## What does “specific enzyme activity” mean?

That’s where the “specific enzyme activity” (aka specific activity) comes in. It says if you send me a certain amount of workers, how many tiles can they lay in an hour. The specific enzyme activity (specific activity): (# of enzyme units per mL)/concentration of protein (mg/mL) -> units/mg or mol/min/mg

What is the specific activity of a recombinant protein?

When a recombinant protein is an enzyme, specific activity is derived from an enzymatic assay. Each enzyme is tested for potency by cleavage of a substrate, and specific activity is expressed as picomoles/minute/microgram.

### What is the difference between specific activity and activity?

Although specific activity is very different from activity, the calculation of specific activity nonetheless is dependent on the activity value, and therefore the stated specific activity value will also be dependent on the enzyme unit definition.

Why is specific activity used to measure enzyme purity?

So specific activity is good for measuring enzyme purity Say you did a serial dilution of an enzyme and you measured its activity at different concentrations the specific activity should be the same since both the numerator & denominator take the concentration into account