Pepsin

Химические свойства

Pepsin is a white or pale yellow powder extracted from the gastric mucosa of pigs, sheep or cattle. Soluble in water, the aqueous solution is acidic. Isoelectric point pH=1. Insoluble in ethanol, chloroform, ether. It is non-toxic and has a special smell of meat; it is hygroscopic. The dry enzyme is relatively stable and will not be inactivated when heated to 1000C for 10min. Its aqueous solution is heated to above 700C or above pH6.2 and begins to inactivate, and when pH>8, it is irreversibly inactivated. It is relatively stable in strong acid solution, and the optimum pH is 1.5-2. Its digestibility is strongest when it contains 0.2% to 0.4% hydrochloric acid (pH 1.6 to 1.8), so it is often used in combination with dilute hydrochloric acid.

Использование

Pepsin is an enzyme that is secreted in the digestive track of mammals. It works to break down proteins into smaller peptides which can readily be absorbed by the small intestine.

Определение

pepsin is an enzyme that catalysesthe breakdown of proteins topolypeptides in the vertebrate stomach.It is secreted as an inactive precursor,pepsinogen.

Подготовка

Pepsin is a stomach enzyme that serves to digest proteins found in ingested food. Production method of pepsin: using porcine gastric mucosa as raw material, after extraction with phosphate buffer solution, use DEAE-cellulose column chromatography, and after acidification, use Sephadex C-25 and Sephadex G-25 column chromatography again to refine the product.

Общее описание

Pepsin powder is prepared from the gastric mucosa of pigs, cattle or sheep.

Методы очистки

Pepsin is re-chromatographed on a column of Amberlite CG-50 using a pH gradient prior to use. Crystallise it from EtOH. [Richmond et al. Biochim Biophys Acta 29 453 1958, Huang & Tang, J Biol Chem 244 1085 1969, 245 2189 1970.]