Detection and characterization of a type IIA secretory phospholipase A2 inhibitory protein in human amniotic fluid.
Two types of phospholipase A2 (PLA2) inhibitory protein (PLIP-I, PLIP-II) were detected and isolated from human amniotic fluid by Sephacryl S300 gel filtration chromatography. The lower molecular weight-fraction (PLIP-II) was further purified by Sephadex G75 gel filtration and analyzed by SDS-PAGE. Its molecular weight was estimated to be approximately 18 kDa, and it was sensitive to heat treatment. Inhibition of phospholipase A2 (sPLA2 type IIA) by PLIP-II occurred in a dose-dependent manner (IC50 about 0.82/microm), and the effect was stronger on sPLA2 IIA than on pancreatic sPLA2 (IC50 about 3.11 microL). The ratio of the inhibitions of the sPLA2 IIA by PLIP-II remained consistent over an entire range of substrate concentrations. Furthermore, addition of excess Ca2+ at concentrations of up to 10 mm did not antagonize the inhibitory activity of PLIP-II.
Moon
T C
TC
College of Pharmacy, Yeungnam University, Kyongsan, Korea.
Lee
J H
JH
Lee
S H
SH
Park
Y K
YK
Baek
S H
SH
Chan
H W
HW
D000328:Adult; D000653:Amniotic Fluid / Q000737:chemistry*; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006023:Glycoproteins / Q000032:analysis* / Q000302:isolation & purification / Q000494:pharmacology; D006801:Humans; D010726:Phosphodiesterase Inhibitors / Q000032:analysis* / Q000302:isolation & purification / Q000494:pharmacology; D010741:Phospholipases A / Q000037:antagonists & inhibitors*; D054467:Phospholipases A2; D011247:Pregnancy; D011817:Rabbits; D013552:Swine
D006023:Glycoproteins; D010726:Phosphodiesterase Inhibitors; C090541:phospholipase A2 inhibitory protein, Naja naja kaouthia; D010741:Phospholipases A; D054467:Phospholipases A2; D002118:Calcium