Pyroglutamic acid (also known as PCA, 5-oxoproline, pidolic acid, or pyroglutamate for its basic form) is an uncommon and little studied amino acid derivative in which the free amino group of glutamic acid or glutamine cyclizes to form a lactam. It is a metabolite in the glutathione cycle that is converted to glutamate by 5-oxoprolinase. Pyroglutamate is found in many proteins including bacteriorhodopsin. N-terminal glutamic acid and 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.

CAS：4042-36-8
中文别名：D-(+)-焦谷氨酸;(R)-(+)-2-吡咯烷酮-5-羧酸;
英文别名：(R)-2-Pyrrolidone-5-carboxylic Acid;D-(+)-Pyroglutamic Acid;(R)-5-Oxopyrrolidine-2-carboxylic Acid;D-Pyroglutamic Acid;(R)-5-Oxopyrrolidine-2-carboxylic acid;(R)-(+)-2-Pyrrolidinone-5-Carboxylic Acid;(2R)-5-oxopyrrolidine-2-carboxylic acid;D-Glutamic Acid Lactam;
分子式：C5H7NO3
分子量：129.114
精确质量：129.043
Psa：66.4
Logp：-0.3216

MDL号：MFCD00066212

外观与性状：白色晶体带有结块
密度：1.38g/cm3
沸点：453.1ºC at 760mmHg
熔点：155-162ºC
闪点：227.8ºC
储存条件：Store at 0-5ºC
蒸汽压：0.002mmHg at 25°C

安全说明：S26-S37/39
危险类别码：R36/37/38
海关编码：2933790090
危险品标志：Xi
危险性防范说明：P261; P305 + P351 + P338
危险性描述：H315; H319; H335
信号词：Warning
危险标志：GHS07