Biology Forum › Molecular Biology › Enzymes
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- August 6, 2012 at 3:36 pm #16734
rk386ParticipantDo 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?
- August 7, 2012 at 3:32 pm #112042jonmoultonParticipant
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.
- August 7, 2012 at 10:08 pm #112043david23Participant
what controls the enzyme levels? your genes, and hormonal regulations which again your genes
- August 7, 2012 at 10:16 pm #112045JackBeanParticipant
you seem to put everything under genes, but genes are controlled by many factors as well
- August 8, 2012 at 6:17 pm #112053rk386Participant
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?
- August 8, 2012 at 6:33 pm #112054JackBeanParticipant
Yes, there are soe well-known examples. For those you don’t know about, you can make some predictions.
- August 8, 2012 at 9:47 pm #112057rk386Participant
Thanks. If I wanted to look more into this, where would I look?
- August 8, 2012 at 10:03 pm #112058JackBeanParticipant
The first choice should be Alberts’ The Cell
- August 8, 2012 at 10:07 pm #112059rk386Participant
Oh, great, I have that.
- August 9, 2012 at 3:19 pm #112062jonmoultonParticipant
Look for "protein turnover". Here’s an introduction. http://en.wikipedia.org/wiki/Protein_turnover
- August 15, 2012 at 4:04 pm #112095rk386Participant
Thanks. Have studies on protein turnover been done for specific proteins, or is it just known in general that that is what happens?
- August 15, 2012 at 4:50 pm #112096jonmoultonParticipant
It has been done for many specific proteins. One good method is pulse-chase analysis. http://en.wikipedia.org/wiki/Pulse-chase_analysis
- August 15, 2012 at 7:03 pm #112097rk386Participant
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?
- August 15, 2012 at 9:21 pm #112098jonmoultonParticipant
Yes.
- August 17, 2012 at 12:11 pm #112108KileYeParticipant
They will degrade through metabolism
- August 20, 2012 at 3:19 pm #112118rk386Participant
What controls that metabolism?
- August 20, 2012 at 3:36 pm #112120rk386Participant
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?
- August 20, 2012 at 10:37 pm #112121jonmoultonParticipant
"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 - August 21, 2012 at 9:15 pm #112126JackBeanParticipant
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.
- August 23, 2012 at 1:00 pm #112153rk386Participant
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?
- August 23, 2012 at 3:30 pm #112154JackBeanParticipant
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?
- August 23, 2012 at 11:10 pm #112157rk386Participant
Do you mean that the same enzyme can be coded for by different genes?
- August 24, 2012 at 2:49 pm #112161JackBeanParticipant
That’s exactly what I mean. Actually most of enzymes is in form of isoenzymes coded by several genes.
- August 24, 2012 at 10:26 pm #112164rk386Participant
Thanks for explaining.
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