Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Isolation and characterization of human membrane carboxypeptidase (HMCP)

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:7164000
;
The authors detected a membrane-bound carboxypeptidase in human placenta and other tissues which cleaves C-terminal Lys or Arg of peptides such as Lys/sup 6/-Met/sup 5/-enkephalin. The enzyme was solubilized from placental microvilli with 0.8% CHAPS and purified 427-fold by ion-exchange chromatography, Sepharose-arginine affinity chromatography, chromatofocusing and gel filtration on HPLC. HMCP had a mol. wt. of 67,000 in SDS-PAGE and 65,300 in gel filtration and a pH optimum of 7.0. HMCP cleaved Bz-Gly-argininic acid the fastest (90 ..mu..mol/min/mg) followed by Bz-Ala-Lys (41), Bz-Phe-Lys (26), Bz-Gly-Arg (1.7) and Bz-Gly-Lys (1.6). Activity was stimulated by CoCl/sub 2/ and inhibited by cadmium acet., o-phenanthroline and 2-mercaptomethyl-3-guanidinoethylthiopropanoic acid but not by phenylmethylsulfonyl fluoride, aprotinin or p-chloromercuriphenylsulfonate. The enzyme was stable for 1 hr at room temp. at pH 4.25, but lost 31% activity at pH 4.0. HMCP did not react with antiserum to human plasma carboxypeptidase N in Western blotting. This study shows that human placental microvilli contain a membrane carboxypeptidase, that differs from other carboxypeptidases, and cleaves C-terminal basic amino acids from peptides. This enzyme could be involved in regulating the level of peptide hormones in the placenta and other tissues.
Research Organization:
Univ. of Illinois College of Medicine, Chicago
OSTI ID:
7164000
Report Number(s):
CONF-8604222-
Conference Information:
Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:4
Country of Publication:
United States
Language:
English

Similar Records

Phosphoenolpyruvate-dependent protein kinase enzyme I of Streptococcus faecalis: purification and properties of the enzyme and characterization of its active center
Journal Article · Mon Feb 11 23:00:00 EST 1985 · Biochemistry; (United States) · OSTI ID:5023380
Reexamination of the binding site for pyridoxal 5'-phosphate in ribulosebisphosphate carboxylase/oxygenase from Rhodospirillum rubrum
Journal Article · Mon Mar 15 23:00:00 EST 1982 · Biochemistry; (United States) · OSTI ID:7071826
Neurospora tryptophan synthase: N-terminal analysis and the sequence of the pyridoxal phosphate active site peptide
Conference · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) · OSTI ID:5233731

Related Subjects

550200 -- Biochemistry
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOLOGICAL EFFECTS
CADMIUM COMPOUNDS
CARBOXYPEPTIDASES
CELL CONSTITUENTS
CELL MEMBRANES
CHLORIDES
CHLORINE COMPOUNDS
CHROMATOGRAPHY
COBALT CHLORIDES
COBALT COMPOUNDS
ELECTROPHORESIS
ENZYME ACTIVITY
ENZYMES
FETAL MEMBRANES
HALIDES
HALOGEN COMPOUNDS
HYDROLASES
ION EXCHANGE CHROMATOGRAPHY
LIQUID COLUMN CHROMATOGRAPHY
MAMMALS
MAN
MEMBRANES
MOLECULAR WEIGHT
PEPTIDE HYDROLASES
PLACENTA
PRIMATES
PURIFICATION
SEPARATION PROCESSES
TRANSITION ELEMENT COMPOUNDS
VERTEBRATES