Talk:Methionine

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Hi, I just edited the main page, sorry I should have asked first, I thought that some foods on the list of rich sources of Methionine were wrong - oranges have comparatively little Methionine as do most fruit and veg compared to nuts or meat. I've based this pre-dominately on this source - http://www.nutritiondata.com/nutrient-search.html (the menu can be used to look at sources of Methionine in the various food groups).

--134.225.163.117 16:19, 29 March 2006 (UTC)

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According to my biochemsitry text, the pKas for Methionine are 2.28 and 9.21, giving an isoelectric point of 5.745. Here, the pKas appear to be incorrect, and they do not give the correct IP of Met.

--Priss 05:06, 10 October 2005 (UTC)

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You know, even if methionine is incorporated into the N-terminal position of a newly synthesized protein, there is no guarantee that in the mature product, it is still the N-terminal amino acid. Some proteins and peptides (for example, insulin) are subjected to the actions of proteases before assuming their mature form. Some proteins have leader sequences that allow them to be transported to their place of action, and the leader sequence is cleaved once transport takes place. David M

Where I work, the people in another lab a few years were trying to label a protein by incorporating sulfur isotope labelled methionine. They tried and tried, and got nowhere... turned out the protein had no methionine. Malcolm Farmer

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"Together with tryptophan, it is the only amino acid needing three bases to encode (nucleotide codon AGT for methionine)."

This makes no sense to me, can someone explain.

Jedi Dan 18:32 Apr 23, 2003 (UTC)

I think I see what the writer intended... I've rewritten it to make it clearer. (I hope) 147.188.60.51

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Does methionine occur in positions other than the N-terminus?

Thanks, has_no_nick

Reply to self:

Yes, it occurs at other positions in some proteins.

I'll just add that on the page. Regards.

"Usually removed"?

Is there any evidence to have the phrase "usually removed by post-translational modification"? If so, can someone put that in. If not, then perhaps the wording shouldn't be as strong (how many proteins in how many species are known to have this phenomenon?).

[edit] SMILES

Currently the SMILES is

C(N)(C(O)O)CCSC

but shouldn't it be

C(N)(C(=O)O)CCSC

? I went ahead and change it but please revert if I'm missing something here. Cburnett 05:06, 19 April 2006 (UTC)

[edit] External link request

Hi. Will you put a link to my site on this page? like this: drugs-about.com/ing/methionine.html Drugs and Health Products containing Methionine

Thank you.

That website does not appear to meet criteria for inclusion because of its highly commercial content and purpose. Please see the guidelines for external links at WP:EL and WP:SPAM. Thanks for asking, though, which is a rarity. Deli nk 17:25, 27 September 2006 (UTC)