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 means specific activity?
Thus, specific activity is defined as the activity per quantity of atoms of a particular radionuclide. It is usually given in units of Bq/kg, but another commonly used unit of activity is the curie (Ci) allowing the definition of specific activity in Ci/g.
What is specific activity in protein purification?
The specific activity is the ratio of the enzyme activity to the total protein. It tells you whether or not your sample became purer following the purification technique. The units of specific activity are micromoles per minute per milligram or unit/mg.
What is the difference between total activity vs specific 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.
Why is specific activity important?
What is Specific Activity? The specific activity of an enzyme defines the purity of an enzyme in a protein mixture. It measures the activity of an enzyme in one milligram of total protein. Hence, this unit is especially important in the purification of enzymes from proteins, in order to assess the purity of the enzyme.
How do you measure protein activity?
The biological activity of a recombinant protein is routinely measured using a bioassay, e.g. chemotaxis or cell proliferation assay, enzyme assay, or a functional ELISA.
What does specific activity mean in enzyme kinetics?
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).
How do you calculate specific activity from Vmax?
The specific activity is Vmax/enzyme concentration. If the enzyme has only one substrate, then it is usually only necessary to measure the rate at a saturating substrate concentration, then divide by the enzyme concentration.
What is the definition of specific activity of an enzyme?
What is Km and Vmax?
Vmax is the maximum velocity of the reaction at which all the enzymes get saturated with the substrate. Km is the concentration of substrate at which half of the maximum velocity is achieved.
Why is it important to calculate 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.