Question

Define the difference between absolute standard versus a relative standard. What type of standard was the gamma-globulin for each of the three test proteins in your experiment? What factors affect the choice of standard protein used?

test protein: lyzozyme, ovalbumin, and gamma-globulin

Answer 1

To determine an unknown protein in the given sample, protein standards are used in the assay. There are two types of protein standards, relative standards, and absolute standards. Absolute standards are proteins that are pure and being assayed. Relative standards are the proteins that are used in the absence of absolute standards and give the same results in comparison to the protein being investigated.

Gamma-globulin is used as a standard protein to assay other proteins under investigation. When used to assay lysozyme and ovalbumin, gamma-globulin acts as a relative standard. While assaying gamma-globulin, gamma-globulin acts as an absolute standard.

The factors that affect the choice of standard protein:

1. Availability – The protein chosen to be standard to assay other proteins must be available easily.
2. Stability – The standard protein must be stable under the conditions, in which the protein assay will be conducted.
3. Cheap – The standard protein must be cheap.

4. Inactive – During protein assay, the standard protein must be inactive in the biochemical reactions.