title: Platelet glycohydrolase activities: characterization and release.
abstract: Granules containing acid hydrolases have been detected in human platelets but have not been thoroughly characterized. We have studied the activity and characteristics of glycohydrolases present in normal human platelets, evaluated their release upon stimulation with thrombin, and assessed the contribution of platelet - released lysosomal contents to the glycohydrolase activity present in normal serum. Platelets contained a remarkable glycohydrolase activity with a prevalence of beta - N-acetylhexosaminidase. All glycohydrolases were released to some extent upon stimulation with thrombin and contributed to the glycohydrolase activity found in human serum. alpha-Mannosidase and alpha-galactosidase were partially inactivated after release by a mechanism as yet undefined. In addition, thrombin stimulation affects the intraplatelet isoenzyme pattern of beta-N-acetylhexosaminidase by producing the appearance of a new form.
authors.affiliation: Dipartimento di Biologia Cellulare e Molecolare, Università di Perugia, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Emiliani
authors.forename: S
authors.initials: S
authors.lastname: Martino
authors.forename: A
authors.initials: A
authors.lastname: Orlacchio
authors.forename: R
authors.initials: R
authors.lastname: Vezza
authors.forename: G G
authors.initials: GG
authors.lastname: Nenci
authors.forename: P
authors.initials: P
authors.lastname: Gresele
mesh_terms: D001792:Blood Platelets / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D002848:Chromatography, DEAE-Cellulose; D003594:Cytoplasmic Granules / Q000201:enzymology / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000097:blood* / Q000378:metabolism; D006098:Granulocytes / Q000201:enzymology; D006801:Humans; D008214:Lymphocytes / Q000201:enzymology; D008247:Lysosomes / Q000201:enzymology / Q000378:metabolism; D008361:Mannosidases / Q000037:antagonists & inhibitors / Q000097:blood / Q000378:metabolism; D010920:Placenta / Q000201:enzymology; D010949:Plasma / Q000201:enzymology; D013917:Thrombin / Q000494:pharmacology; D000519:alpha-Galactosidase / Q000037:antagonists & inhibitors / Q000097:blood / Q000378:metabolism; D043323:alpha-Mannosidase; D001619:beta-N-Acetylhexosaminidases / Q000097:blood / Q000378:metabolism
chemical_list: D006026:Glycoside Hydrolases; D008361:Mannosidases; D000519:alpha-Galactosidase; D043323:alpha-Mannosidase; D001619:beta-N-Acetylhexosaminidases; D013917:Thrombin