Carboxypeptidase A in mouse mast cells. Identification, characterization, and use as a differentiation marker.

摘要: By using a conventional spectrophotometric assay with hippuryl-L-phenylalanine as the substrate, 10(6) BALB/c mouse serosal mast cells possessed 1.5 +/- 0.43 U (mean SE, n = 5, range 0.48 to 2.5) of carboxypeptidase A activity, while T cell factor-dependent, bone marrow-derived (BMMC) had barely detectable levels 0.01 0.001 U/10(6) 3). In order characterize present in BMMC, sensitive was developed that used angiotensin I substrate and reverse phase-high performance liquid chromatography separate quantify production cleavage product des-leu-angiotensin I. Using this assay, BMMC neutral basic pH optimum hydrolyzed Km 0.78 mM. The antigen-induced net percent release from IgE-sensitized proportional secretory granule component beta-hexosaminidase which indicates location for exopeptidase. As defined by exclusion during Sepharose CL-2B chromatography, exocytosed greater than 1 X 10(7) m.w. complex bound proteoglycans. Because cocultured skin-derived 3T3 fibroblasts are known undergo an increase histamine content biosynthesis 35S-labeled heparin proteoglycans, activity measured BMMC/fibroblast coculture 0 28 days. increased progressively days co-culture 0.004 0.002 starting 3) 0.36 0.10 co-cultured cells. These findings indicate A, protease, is granules proteoglycan vitro differentiation mucosal-like serosal-like