title: Purification of human lung angiotensin-converting enzyme by high-performance liquid chromatography: properties and N-terminal amino acid sequence.
abstract: Angiotensin-converting enzyme from the human lung was purified to apparent homogeneity, using high-performance liquid chromatography following trypsin treatment of the detergent-extract. A 1,750-fold purification was achieved with a 26% yield. The specific activity of the enzyme was 105 units per mg protein with the substrate hippuryl-L-histidyl-L-leucine (HHL) at 37 degrees C, and the Km value for HHL was 1.9 mM. The molecular weight was estimated to be 170,000 by sodium dodecyl sulfate gel electrophoresis, and the isoelectric point was about 4.8, by chromatofocusing. The N-terminal amino acid sequence was (NH2)-X-X-Pro-Gly-Leu-Glu-Pro-Gly-X-Phe-Ser-Ala-Arg-Glu-Ala-Gly-Ala. This is highly homologous to the corresponding sequences of the enzymes from bovine and rabbit lung and from pig, bovine, and mouse kidney, but significantly different from that of the human kidney enzyme.
authors.affiliation: Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo.
authors.forename: K
authors.initials: K
authors.lastname: Takeuchi
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
authors.forename: N
authors.initials: N
authors.lastname: Ohishi
authors.forename: Y
authors.initials: Y
authors.lastname: Seyama
authors.forename: F
authors.initials: F
authors.lastname: Takaku
authors.forename: H
authors.initials: H
authors.lastname: Yotsumoto
mesh_terms: D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003902:Detergents; D006801:Humans; D007527:Isoenzymes; D008722:Methods; D008969:Molecular Sequence Data; D008970:Molecular Weight; D007703:Peptidyl-Dipeptidase A / Q000302:isolation & purification* / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism
chemical_list: D003902:Detergents; D007527:Isoenzymes; D007703:Peptidyl-Dipeptidase A; D014357:Trypsin