title: Purification and partial characterization of platelet-derived adherence-inhibiting factor in guinea pig.
abstract: Purification and partial characterization of adherence-inhibiting factor (AIF) of platelet-granule fraction in guinea pig were studied. When freshly prepared platelet-granule fraction was subjected to a gel filtration, two neutrophil adherence-inhibiting peaks, designated AIF-I (2,800 kDa) and AIF-II (12 kDa), appeared. AIF-I was sensitive to diisopropylfluorophosphate (DFP) and originated from lysosomes, whereas AIF-II was insensitive to DEP and localized in alpha-granules. Both AIFs were released from platelets by a thrombin stimulation. As the total activity of AIF-I was about 5-fold higher than that of AIF-II, AIF-I was purified and characterized. When purified AIF-I was analyzed on SDS-polyacrylamide gel electrophoresis, the 340 kDa protein band and the other large protein band were observed. Under reducing condition, AIF-I was separated into three components (340, 190 and 165 kDa). AIF-I significantly inhibited neutrophil adherence to artificial substrata and to type IV collagen-coated plastic surface, but not to fibronectin- or plasma-coated plastic surfaces, suggesting that AIF-I inhibits neutrophil adherence not only via nonspecific adsorption sites but also via type IV collagen receptors.
authors.affiliation: Department of Biochemistry, School of Medicine, Juntendo University, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Iwabuchi
authors.forename: T
authors.initials: T
authors.lastname: Yamashita
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000502:physiology* / Q000648:ultrastructure; D002352:Carrier Proteins / Q000302:isolation & purification* / Q000502:physiology; D002448:Cell Adhesion; D002458:Cell Fractionation; D002501:Centrifugation, Zonal; D002850:Chromatography, Gel; D003594:Cytoplasmic Granules / Q000032:analysis / Q000648:ultrastructure; D004591:Electrophoresis, Polyacrylamide Gel; D006168:Guinea Pigs; D007525:Isoelectric Focusing; D007531:Isoflurophate / Q000494:pharmacology; D008297:Male; D008970:Molecular Weight; D009504:Neutrophils / Q000166:cytology / Q000502:physiology
chemical_list: D002352:Carrier Proteins; D007531:Isoflurophate