Enzymes

[rk386]

Do enzymes in the body last permanently, or do they over time get broken down and then replenished/rebuilt/replaced? Also, what controls the amount of enzyme present?

[jonmoulton]

Enzymes are degraded over time. Some are relatively short-lived while others are very persistent, but damage accumulates and they are eventually broken down.

This page might help the system make more sense.

http://en.wikipedia.org/wiki/Proteolysis

[david23]

what controls the enzyme levels? your genes, and hormonal regulations which again your genes

[JackBean]

you seem to put everything under genes, but genes are controlled by many factors as well

[rk386]

Thanks. Follow-up question:

Enzymes are degraded over time. Some are relatively short-lived while others are very persistent, but damage accumulates and they are eventually broken down.

Is it known which types of enzymes break down quickly and which are persistent?

[JackBean]

Yes, there are soe well-known examples. For those you don't know about, you can make some predictions.

[rk386]

Thanks. If I wanted to look more into this, where would I look?

[JackBean]

The first choice should be Alberts' The Cell

[rk386]

Oh, great, I have that.

[jonmoulton]

Look for "protein turnover". Here's an introduction. http://en.wikipedia.org/wiki/Protein_turnover

[rk386]

Thanks. Have studies on protein turnover been done for specific proteins, or is it just known in general that that is what happens?

[jonmoulton]

It has been done for many specific proteins. One good method is pulse-chase analysis. http://en.wikipedia.org/wiki/Pulse-chase_analysis