Unit Definition

在 pH 5.6 和 25°C 下，一单位每分钟可将胰蛋白酶原转化为 1.0nmol 的胰蛋白酶。

Physical form

含有磷酸钠缓冲盐的冻干粉

Application

Enterokinase from porcine intestine has been used in a study to investigate complementary DNA cloning and sequencing of rat enteropeptidase. Enterokinase from porcine intestine has also been used to learn more about the insulinotropic region of the gastric inhibitory polypeptide.

The enzyme from Sigma has been used to activate zymogens in order to detect trypsin activity. The study to investigated the structural and evolutionary consequences of unpaired cysteines in trypsinogen. The product has been used to measure trypsin while studying the effect of pesticide induced alterations in gene expression in the lobster, Homarus americanus The enzyme from Sigma has been used to develop a novel assay for measuring levels of lipid-free apoA-I in the presence of lipid-bound apoA-I. Enteropeptidase can specifically cleave human lipid-free apoA-I but not its lipid-bound form resulting in an N-terminal fragment of 22 kDa. It has also been used in a study to examine the effect of calcium and phytic acid on the activation of trypsinogen and the stability of trypsin.

Biochem/physiol Actions

Enterokinase is a membrane bound serine protease that specifically and rapidly converts trypsinogen to trypsin, thereby, triggering the conversion of other zymogens to active enzymes. It has a molecular mass of approximately 150 kDa. The enzyme is a heterodimer consisting of 35-47 kDa subunits. The light and the heavy chains are linked by two disulfide bridges. It is a glycoprotein containing 35% carbohydrate. The polypeptide chain of trypsinogen is hydrolyzed only after an -(Asp)₄-Lys- sequence. The enzyme is inhibited by soybean trypsin inhibitor. Enterokinase is typically used in protein modification and amino acid sequence determination.