residue of a stupid question

[Brian the Roman]

In my reading of this forum, I come across the term 'residue' from time to time. Is this a term for amino acids? Or their side chains? :confused:

ms

[Brian the Fist]

residue = amino acid residue - called a residue because a 'free' amino acid has an extra H2O attached to it. When two amino acids bond together to form a peptide, they lose a water molecule in forming the peptide bond between them, so whats left is the amino acid 'residue'. (Probably more detail than you wanted :eek:)

[Alpha_7]

Thanks for the detail... I was enjoying being in the dark, but its easier to pimp the project to others, when you *actually* sound like you know whats going on... :D

[Brian the Roman]

Thanks Howard. And the level of detail was just what I was after. I'd forgotten my High School chemistry. The level of detail was fine.

[Brian the Roman]

oops hit enter too soon... if two amino acids bond to form a peptide, and a protein is a collection of AAs, what's the difference between a peptide and a protein?

ms

[Brian the Fist]

A peptide is just generally shorter than a protein, but no real difference. Basically a piece of a protein is referred to sometimes as a peptide or polypeptide.