The amino-acid alphabet
Peptides
spelled out
A peptide is a short chain of amino acids, written as a string of one-letter codes from the free amine end to the free acid end. Twenty standard letters cover the usual amino acids, and their order decides what the chain does. Every article here is filed as an element in a table, with the evidence behind it named. Learn the letters
39 elements20 letters4 families
Cys ยท Special
Cysteine
Two cysteines can fuse into a sulfur bridge that locks a shape.
Changes the chain itself: bends it, bridges it or keeps it flexible.
- 01
The evidence is named
Each claim says whether it rests on cells, animals or people, and what that kind of study cannot show.
- 02
Jargon is defined on arrival
A term is explained where it first appears; the glossary holds the rest.
- 03
Gaps are admitted
Unknown is not the same as safe, and not the same as useless. We say which one we mean.