Enzymes

[rk386]

Thanks. It is pretty amazing what technology can do. So by this method, the rate at which a protein breaks down can be determined, e.g. an enzyme?

[jonmoulton]

Yes.

[KileYe]

They will degrade through metabolism

[rk386]

What controls that metabolism?

[rk386]

Also, in terms of the rate at which an enzyme acts, other than substrate concentration and reaction rate, are there any other conditions that would regulate the rate at which an enzyme works? Are there such thing as inherently "slower" or "faster" enzymes?

[jonmoulton]

"Also, in terms of the rate at which an enzyme acts, other than substrate concentration and reaction rate, are there any other conditions that would regulate the rate at which an enzyme works? Are there such thing as inherently "slower" or "faster" enzymes?"

Oh my goodness yes yes yes. Different protein structures have different rates of catalysis - a single amino acid change can alter or eliminate activity. Temperature and pH affect rate. Many enzymes are controllable by other enzymes -- look at allosteric regulation:
http://en.wikipedia.org/wiki/Allosteric

[JackBean]

Assuming you mean regulation of rate of one enzyme, then you're interested in things such as posttranslational regulation (phosphorylation). As jonmoulton mentioned, allosteric regulators are important.

[rk386]

So there is a difference between the regulation of the rate of one enzyme as compared to the regulation of the rate of many enzymes? How does the regulation of many enzymes work?

[JackBean]

What I meant is the regulation of enzyme produced by one gene. On the other hand, as jonmoulton wrote, you can have several genes and the respective proteins will have different amino acids in active side, they may be localized in different compartments etc. But I do not consider this much as regulation, because you must have the gene already, so it's not really something you can regulate, right?

[rk386]

Do you mean that the same enzyme can be coded for by different genes?

[JackBean]

That's exactly what I mean. Actually most of enzymes is in form of isoenzymes coded by several genes.

[rk386]

Thanks for explaining.