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Name: Russell
Status: Student
Grade:  9-12
Location: N/A
Country: United States
Date: July 2008

Cannot find a definite answer to the following question: Explain what is meant by biological activity of a protein?

The biological function of a protein is either structural (collagen, for example), carrier (hemoglobin, for example), enzymatic (trypsin, for example), regulatory (receptor proteins and insulin, for example), mechanical (myosin, for example). Google "functions of proteins" for others.

Good luck,

Ron Baker, Ph.D.

In general, proteins are designed to 'attach' to biological molecules. They might attach to each other to form structural units in the cell, or they might attach to other biological molecules to do specific tasks (such as catalyze a chemical reaction). These functions are known as the protein's 'biological activity'.

A protein is like a long string that is folded around itself in a specific way. If the protein comes unfolded or is folded in the wrong way, it may no longer be able to perform its function. When this happens, we say it has lost its biological activity. In the case of chemical reactions, you can quantitatively measure how fast the reaction occurs, and measure a quantitative biological activity (for example, to compare two proteins' ability/speed to break down a sugar).

Some laboratory techniques that measure protein cannot tell if the protein is active or not -- they can only tell if the protein is present or how much there is. Thus, you may measure that protein is present in a sample, but if the protein has been degraded in some way, you may not measure any biological activity. That's why biologists make a distinction between amount of protein and biological activity.

Hope this helps,

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