出典:Wikipedia
出典:『Wikipedia』 (2011/04/27 22:00 UTC 版)
Pyroglutamic acid (also known as 5-oxoproline, pidolic acid, or pyroglutamate for its basic form) is an uncommon amino acid derivative in which the free amino group of glutamic acid cyclizes to form a lactam. It is found in many proteins including bacteriorhodopsin. N-terminal glutamine residues can spontaneously cyclize to become pyroglutamate. This is one of several forms of blocked N-terminals which present a problem for N-terminal sequencing using Edman chemistry, which requires a free primary amino group not present in pyroglutamic acid. The enzyme pyroglutamate aminopeptidase can restore a free N-terminus by cleaving off the pyroglutamate residue.