Detail of "7436-62-6"

Reference

Kinetic studies on the inhibition by prostaglandins and cyclic GMP of multimolecular forms of human pregnancy serum and placental oxytocinase

Kinetic studies on the inhibition by prostaglandins and cyclic GMP of multimolecular forms of human pregnancy serum and placental oxytocinase. Roy, Ashim C.; Yeang, Michael; Mian, Tan Suan; Kottegoda, Sri R. (Kandang Kerbau Hosp., Natl. Univ. Singapore, Singapore 0821, Singapore). IRCS Med. Sci., 12(3), 203 (English) 1984. CODEN: IMSCE2. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) Section cross-reference(s): 7 The kinetic data of the oxytocinase [9031-41-8] isoenzymes of serum from pregnant women (30-40 wk of gestation) and normal fullterm human placenta and their inhibition by prostaglandins (PGs) and cGMP [7665-99-8] were detd. The Km and Vmax values of the isoenzymes using either S-benzyl-L-cysteine-p-nitroanilide (BCN) [7436-62-6] or L-leucine-p-nitroanilide (LN) [4178-93-2] as substrate were independent of pH. At either pH 6.2 or 6.8, the Km and Vmax of the 3 placental isoenzymes (PI, PII, and PIII) were significantly greater with LN than BCN. With both substrates at either pH, there was no significant difference in the Ki values among the PGs studied against the serum and placental isoenzymes. However, using LN as substrate, the Ki of PGE1 [745-65-3] was higher against PII than against the other isoenzymes. Generally, inhibition by PGs of all the isoenzymes was more effective at pH 6.2 than 6.8 using either substrate and with LN than BCN at either pH. 8-Bromo-cGMP [31356-94-2] was more potent than cGMP, and both compds. demonstrated higher affinity for all the isoenzymes at pH 6.2 than 6.8 and with BCN than LN as substrate. Thus, the relative potencies of PGs and cGMPs are similar.