title: Inhibition of human leukocyte elastase activity by heparins: influence of charge density.
abstract: Heparins with different structures and physico-chemical properties were evaluated for their capacity to inhibit human leukocyte elastase activity in vitro by using a chromogenic substrate. Heparin from bovine intestinal mucosa and heparan sulfate from bovine spleen were extracted and purified, and their purity, structures, and physico-chemical properties were evaluated. Slow moving and fast moving heparin species were obtained by selective precipitation as barium salt, and partially desulfated and re-N-sulfated heparin was produced by chemical modifications. Heparins with different molecular mass (from 950 to 7820), narrow polydispersity and the same charge density were produced by a chemical depolymerization process in the presence of free radicals, and further gel-permeation chromatography. Heparins strongly inhibit elastase activity, and there is a significant linear dependence between charge density (sulfate-to-carboxyl ratio) and enzymatic activity. We also found a significant linear correlation between the percentage of N-sulfate groups and increased inhibition of elastase activity and between the percentage of iduronic acid and enzymatic activity. Heparin samples with a M(r) greater than about 2000-3000 inhibit the HLE activity to the same extent (about 59%) whilst two fractions with a M(r) of 1530 (29% inhibition of HLE activity) and 950 (4% inhibition of HLE activity) have less capacity to produce a decrease in the enzymatic activity.
authors.affiliation: Department of Biologia Animale, University of Modena, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Volpi
mesh_terms: D000818:Animals; D002417:Cattle; D004187:Disaccharides / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006025:Glycosaminoglycans / Q000737:chemistry / Q000494:pharmacology*; D006493:Heparin / Q000737:chemistry / Q000494:pharmacology; D006497:Heparan Sulfate / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D019272:Leukocyte Elastase; D008970:Molecular Weight; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors*; D011199:Potentiometry; D013329:Structure-Activity Relationship
chemical_list: D004187:Disaccharides; D004791:Enzyme Inhibitors; D006025:Glycosaminoglycans; D006493:Heparin; D006497:Heparan Sulfate; D019272:Leukocyte Elastase; D010196:Pancreatic Elastase