BIOCHEMICAL PROPERTIES OF CARBOXYPEPTIDASE A OF THE UNTRANSFERRED TISSUE AND MALIGNANT NEOPLASM OF THE MAMMARY GLAND.

To study biochemical properties of carboxypeptidase A of the untransformed tissue and malignant neoplasm of the mammalian gland. Sampling of anatomical materials for research was conducted with compliance of ethical and legal standards. Excretion of this enzymes includes gradual fractionation with the (NH4)2SO4, dialysis at the presence of 2,0 мМ Zn++ and gel chromatography on the sephadex - G 75. The investigation substrate specificity of the enzymes was held by hydrolysis of the substrate of carbobenzoxyphenylalanine, phenylalanylalanine, glutamyltyrosine, prolylalanine (2,0 mM), haemoglobin and casein (2,0 %). The influence of inhibitors and activators was determined in presence of: Zn++, cysteine, triton X-100, soybean trypsin inhibitor, leupeptin, pepstatin, PHMB, PMSF, dimethylmolyemydanhydride, tozylheptanol, mercaptoethanol, EDTA and 1,10 - phenanthroline. The maximal velocity (Vmax), Mihaelis constant (Km), inhibition type and inhibition constant (Ki) analysed by Lineweaver - Burk method. Carboxypeptidase A from the untransformed tissue and malignant neoplasm of the mammalian gland better splits the substrates, which have hydrophobic and aromatic amino acids. The activity of carboxypeptidase A from the malignant tumor of the mammalian gland is inhibited most of all under influence of soybean trypsin inhibitor and PMSF, in contrast to untransformed tissue. For carboxypeptidase A from the untransformed tissue of the mammalian gland Km=0,24 mM and Ki=0,40 mM were determined, for carboxypeptidase A from the malignant neoplasm of the mammalian gland - Km=0,17 mM and Ki=0,65 mM. Carboxypeptidase A from the untransformed tissue and malignant neoplasm of the mammalian gland is identical as to the substrate specificity, inhibition by phenylalanine for noncompetitive type, inhibition and activation effect by reagent with the exclusion of soybean trypsin inhibitor and PMSF, but differ as to affinity to carbobenzoxyphenylalanine and sensitivity to phenylalanine.