help!!!

Genetics as it applies to evolution, molecular biology, and medical aspects.

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Anita ru
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help!!!

Post by Anita ru » Mon Apr 16, 2007 2:19 am

In the peptide synthesis,how to choose resins in terms of sequence ?

blcr11
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Post by blcr11 » Mon Apr 16, 2007 3:37 pm

Not sure I understand the question. I assume you’re talking about peptide synthesis—as in solid phase peptide synthesis—not biological synthesis of proteins on ribosomes, even though this is a Genetics board. There are two major solid-phase methods for peptide synthesis; BOC-protected methods, the original Merrifield solid-phase method which used HF for the final cleavage reaction to free the peptide product from the resin; and fMOC-protected methods which (I think) uses the milder, or at least easier to use reagent, TFA, for final cleavage. Both methods traditionally used (different) derivatized polystyrene resins—though I know there are other possible choices, I’m not enough of a synthetic chemist to know very much about them. You can choose to add a protected amino acid to an unmodified resin, but most people buy tBOC- or fMOC-amino acids already attached to a resin. I guess I never thought that the ultimate sequence of the peptide dictated the choice of resin, unless it has something to do with “difficult” residues like cysteines or methionines, for example—but then, I’m not a peptide chemist, either.

EMDNovabiochem (one of many potential sources) sells t-BOC and fMOC amino acid resins and also makes available technical notes that may be helpful. Try these:

http://www.emdbiosciences.com/SharedIma ... osterE.pdf
http://www.emdbiosciences.com/SharedIma ... locksE.pdf

If you have access to a library that carries Methods in Enzymology, Volume 289 (1997) is an issue on solid phase methods.

The classic in the field is Miklos Bodanszky's Principles of Peptide Synthesis, last updated in 1993.

novo'
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Post by novo' » Sun May 13, 2007 10:36 am

mRNA synthesizes proteins in the ribosome, that might be of help to you, but... peptide synthesis ?! hmmm

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