胃蛋白酶 来源于猪胃粘膜 *Sigma货号：P7012-1g

生化/生理作用

Pepsin can hydrolyze peptide bonds, not amide or ester bonds. Pepsin can hydrolyze peptides with aromatic acids on either side of the peptide bond. The closer the sulfur-containing amino acid is to the peptide bond, the easier it is to hydrolyze. Pepsin preferentially cleaves the carboxyl side of phenylalanine and leucine, as well as the carboxyl side of glutamate residues. Cut the Phe Val, Gln His, Glu Ala, Ala Leu, Leu Tyr, Tyr Leu, Gly Phe, Phe Phe, and Phe Tyr bonds of the insulin beta chain. Pepsin is the main proteolytic enzyme produced by the stomach. It digests proteins by cleaving internal peptide bonds. [6] This enzyme does not cleave valine, alanine, or glycine bonds. [7] Z-L-tyrosyl-L-phenylalanine, Z-L-glutamyl-L-tyrosine, or Z-L-methionine tyrosine can be used as substrates for gastric digestion. [7] Pepsin is inhibited by various peptides containing phenylalanine. [9] Priority cracking: hydrophobicity and aromatic residues at P1 and P1 'positions. Degradation of Phe Val, Gln His, Glu Ala, Ala Leu, Leu Tyr, Tyr Leu, Gly Phe, Phe Phe, and Phe Tyr bonds in the β - chain of insulin

单位定义

一个酶活性单位是指在使用血红蛋白作为底物的三氯yi酸（TCA）可溶性产物测量中，在37°C、pH 2.0条件下每分钟产生0.001的ΔA280 所需的酶量
（终体积 = 16 mL
光程 = 1cm
）

分析说明

E1%/280=14.7
最适pH值为2-4
在4 M尿素和3 M盐酸胍中可保持活性
在60°C时稳定
胃蛋白酶在pH 8.0-8.5下发生不可逆灭活
蛋白质由E1%/280测定