Transamidating enzymes in maternal plasma and placenta in human pregnancies complicated by intrauterine growth retardation.
Transamidases are enzymes, which are necessary for normal clot formation. They fall into two types: thrombin-dependent Factor XIII and thrombin-independent tissue transglutaminases. The investigation showed that human placenta contains not only Factor XIII, but also considerable amounts of a tissue trans-glutaminase identical with an enzyme present in red blood cells. A quantitative assay for transamidases, using incorporation of radioactively labelled putrescine into casein, was applied to placental extracts. With this assay the amounts of thrombin-dependent and thrombin-independent transamidases were determined in the placenta of fullterm infants and term infants who were small for gestational age. The transamidase activities of the placenta in the two groups showed no statistically significant difference. Plasma Factor XIII subunit a antigen concentration was increased by about 40% in midpregnancy and returned to normal nonpregnant values in the 3rd trimester, but when intrauterine growth was retarded the plasma Factor XIII concentration remained elevated. Plasma Factor XIII activities showed a similar variation.
D005176:Factor XIII / Q000378:metabolism*; D005260:Female; D005317:Fetal Growth Retardation / Q000201:enzymology*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D005723:gamma-Glutamyltransferase / Q000097:blood*
D005176:Factor XIII; D005723:gamma-Glutamyltransferase