minor/major Amino acids

[piefke]

Hi everybody,

sometimes the amino acids are divided into the minor and major AA´s. But I don´t find any definition for minor and major amino acids... What are they??

[kolean]

Major amino acids are the main 20 amino acids that you learn in your textbooks, but there are hundreds of them (mostly modified major amino acids) and these are the minor ones.
http://www.imagerynet.com/amino/classification.html

[Darby]

I thought that the minor ones were the ones that were vary rarely used in human proteins and so weren't big dietary needs...but I could be wrong...

[MrMistery]

well darby what are you referring to? Humans require intake of 9 amino acids (the essential ones) because they can't make them - how much of them proteins use is not a factor. And considering how many proteins there are, I would think that amino acids are used at about the same rate, is there any info to prove the contrary?

I would have defined minor amino acids as amino acids that get incorporated into proteins as-is, like the 20 canonical amino acids. The two most well characterized are selenocysteine and pyrolysine, but I'm sure there are others. Of course, this is just my gut instinct, I don't know any books to pack this up

[JackBean]

well darby what are you referring to? Humans require intake of 9 amino acids (the essential ones) because they can't make them - how much of them proteins use is not a factor. And considering how many proteins there are, I would think that amino acids are used at about the same rate, is there any info to prove the contrary?

I don't think so. Such amino acids like methionine or tryptophane are used just rarely (I think), on the other hand, such like alanine and all these small amino acids (and of course some others too) are used moch more widespreadly.

[Darby]

Apparently whether amino acids fall into the same "major / minor" categories as other nutrients is somewhat undecided and controversial.

I think what's being discussed here may be more semantic - essential/nonessential being used as a synonym for major / minor.

http://jn.nutrition.org/cgi/content/full/127/9/1842

http://journals.cambridge.org/action/di ... aid=800520

http://www.fao.org/docrep/MEETING/004/M ... 772E00.HTM