title: [Hydrolysis of prolactin by a serine proteinase from mammary gland secretory cell mitochondria].
abstract: Mitochondrial proteinase isolated from secretory cells of the mammary gland of lactating rats able to hydrolyze 125I-labeled and native prolactin (PRL) has been studied. The enzyme represents a serine proteinase and is localized in the inner mitochondrial membrane. The molecular mass of the enzyme is 17-18 kDa, pH optimum is at 8.0-9.0. Partial purification of the enzyme has been carried out. The Km constant for 125I-PRL is equal to 10(-6) M, that for 2% hemoglobin is 1.2 x 10(-4) M. Analysis of products of rat and ovine PRL hydrolysis by proteinase using high performance liquid chromatography and PAAG electrophoresis revealed the formation of large-size fragments of the hormone. A possible role of proteinase in the mechanism of PRL action on mammary gland tissues is discussed.
authors.forename: R P
authors.initials: RP
authors.lastname: Khropycheva
authors.forename: G V
authors.initials: GV
authors.lastname: Marinchenko
authors.forename: V A
authors.initials: VA
authors.lastname: Fedosimov
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006868:Hydrolysis; D007425:Intracellular Membranes / Q000201:enzymology; D007457:Iodine Radioisotopes; D007774:Lactation; D008321:Mammary Glands, Animal / Q000201:enzymology*; D008928:Mitochondria / Q000201:enzymology*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012697:Serine Endopeptidases / Q000378:metabolism*
chemical_list: D007457:Iodine Radioisotopes; D011388:Prolactin; D012697:Serine Endopeptidases
vernacular_title: Gidroliz prolaktina serinovoĭ proteinazoĭ mitokhondriĭ sekretornykh kletok molochnoĭ zhelezy.