Glutathione (biochemistry)

[zieglernatta]

Hello friends! I'm a second year medical student and I could use some help with the following question about biochemistry:

 

Name 2 reasons why glycine is added to glutamate and cysteine in glutathione (GSH).

 

Thank you!

[hypervalent_iodine]

Alright, so given that this is a homework question I can't outright give you the answer. There is one major point you should consider here:

 

- Glutathione is a tripeptide.

 

So you need to ask yourself: what is it made out of? The answer should be pretty obvious once you work that out. You should make use of the wikipedia article on glutathione if this is still puzzling you. Failing that, please feel free to ask some more specific questions about what you're having trouble with

[zieglernatta]

Thank you but you didn't answer my question! What I meant was:

 

What is the purpose of glycine in glutathione rather than what is added to cysteine and glutamate to make glutathione.

 

I already read wikipedia but I couldn't figure it out.

 

All the best!

[hypervalent_iodine]

Thank you but you didn't answer my question! What I meant was:

 

What is the purpose of glycine in glutathione rather than what is added to cysteine and glutamate to make glutathione.

 

I already read wikipedia but I couldn't figure it out.

 

All the best!

 

Ah, ok. You should be a little clearer in your questions to solve confusion.

 

The question still seems a little vague, but I suspect I know where it is wanting you to go with it. You should consider the structure-activity relationship between the amino acid residues in GSH and glutathione S-transferase - i.e. how it is associated with the binding pocket of the enzyme, etc. Glycine having no real functional side chain doesn't normally participate in many enzymatic reactions, so I suppose you need to as yourself what else it might be doing?

 

I found this paper, which may be of some assistance. If I'm still not on the right track with what you want, I apologise. Please be a little clearer with what you're actually needing so we can better help you

 

 

 

 

[zieglernatta]

looks like it acts acts as a catalyst?

[spin-1/2-nuclei]

looks like it acts acts as a catalyst?

 

Hello,

 

Hypervalent is right, your question is strangely worded. I wouldn't have known how to help you without reading your exchanges so far - and I am still not certain if I understand what you are asking.

 

So,

1. if you are asking what is the reason for having glycine in GSH - then please continue on to the questions below.

2. If you are asking something else, please restate your question.

 

 

Questions:

Ask yourself the following questions to obtain your answer:

 

1. What makes glycine unique among the amino acids?

 

2. Where is glycine in the structure of GSH.

 

3. Once you've researched the chemistry of glycine, what important aspects of glycine's unique chemistry are maintained once covalently bound in GSH?

 

4. What does GSH do in the body?

 

5. What of GSH's functions in the body are assisted via glycine - i.e. - what role does glycine play in GSH's chemistry?

 

Hope this helps.. best of luck with your studying

Cheers

 

edit: you may also find this useful - http://docs.google.com/viewer?a=v&q=cache:0kOkXzcofc4J:www.sfrbm.org/frs/DickinsonGSHSynthesis.pdf+synthesis+of+glutathione&hl=en&gl=za&pid=bl&srcid=ADGEEShemEMxJweqlJDaBhTlgCtuXJvxtzn-aRR21BkQMznHv_U3UDRHQg79oTmhdS0kyvYEa4nt_xn4y7vciACF1_M1o3iDHFIhI7UvQcrHCV18f8akXbrGzSkgJklWs6Bfb3w1th6C&sig=AHIEtbRfkgRrC9Il3N5TFCPvfWfrunEj1Q

Edited August 31, 2011 by spin-1/2-nuclei

[zieglernatta]

Thanks a lot and sorry for the confusion, as they say: lost in translation!