Charactarization and localization of kndothfi.in 1 i nconvhrthdby human chymasf

Human chymase has a high specificity tor the en.version of angio teiisin I to angiotensin II in cardiac and vasculn: ','ssucs. We report here that human chymase clea\ed at Tyr' <i'v:- peptitie bound of dig FT 1 and converted to HT l t .M. Big KI ! uid mit contract in porcine coronary artery, hut chymase produced i,l I i n showed a potent \asocontricti\e actions, although subtly less potent than that of HT 1. Immunohistochcmical staining o' 'ijman coronary atheroma using a specific HT-1 i <i Ig(i purified '> affinity column Chromatograph) revealed that FT 11 i like t-oivity was present in the shoulder and adxentitia resion of a co:-M,ar\ atheroma. When the same area v%as stained with anti chyr/ase antibody, chymase and FT 11 <i were colocalized in the co>'<"Mry atheroma. In addition to that, primai) imirinc bone marrow rna-4 cells(BMMC') contained and secreted HT 1 (New-Biol.4(2: 147 56.1942).These results suggest that the mccha nisms of endothclin production and secretion may exist, or be con corned with chymase in human mast cells. The results indicated that HI 11 i may have a novel biological function tor coronary atheroma.