MEMBRANE-BOUND THERMOLYSIN-LIKE METALLOENDOPEPTIDASE: PURIFICATION AND CHARACTERIZATION OF THE ENZYME FROM RABBIT KIDNEY AND BRAIN. IDENTIFICATION OF A SIMILAR ENZYME IN HUMAN SERUM AND STUDY OF ITS ACTIVITY IN SARCOIDOSIS.
Item
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Title
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MEMBRANE-BOUND THERMOLYSIN-LIKE METALLOENDOPEPTIDASE: PURIFICATION AND CHARACTERIZATION OF THE ENZYME FROM RABBIT KIDNEY AND BRAIN. IDENTIFICATION OF A SIMILAR ENZYME IN HUMAN SERUM AND STUDY OF ITS ACTIVITY IN SARCOIDOSIS.
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Identifier
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AAI8401914
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identifier
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8401914
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Creator
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ALMENOFF, JUNE SHERIE.
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Contributor
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Marian Orlowski
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Date
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1983
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Biochemistry
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Abstract
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A membrane-bound metalloendopeptidase from bovine pituitaries, rabbit kidney, and rabbit brain was shown to hydrolyze peptide bonds involving the amino group of hydrophobic amino acids in natural and synthetic peptides. Evidence is presented that this enzyme is identical with enkephalinase.;The enzyme {lcub}EC 3.4.24.11{rcub} was purified to homogeneity from rabbit kidney and partially purified from rabbit brain. It has a molecular weight of about 95,000 and is inhibited by metal chelators and by the active site directed inhibitors phosphoramidon and thiorphan.;N-(1-carboxy-2-phenylethyl) derivatives of phenylalanyl, alanyl, and glycyl-pAB were synthesized as potential inhibitors of the enzyme. The two diastereomers of the phenylalanyl derivative were separated; the more potent isomer had a K(,i) of 2.9 x 10('-8) M. The inhibitory potency of the alanyl and glycyl derivatives was lower by several orders of magnitude. The data suggest that a hydrophobic residue in the P(,1)' position and a carboxylate group coordinating with the active site zinc account for the inhibitory action of these compounds.;The enzyme from rabbit brain was compared with the rabbit kidney enzyme. The two enzymes had the same pH optimum, molecular weight, and specificity, however, minor but significant differences were found in their interactions with specific inhibitors and antisera.;N-(1-carboxy-2-phenylethyl) derivatives of phenylalanyl, alanyl, and glycyl-pAB were tested for antinociceptive activity. Intraperitoneal administration of all three compounds produced significant analgesia that lasted for 24 h. The data indicate, however, that the analgesia observed does not correlate with the K(,i) values of the inhibitors.;An enzyme with properties similar to the membrane-bound metalloendopeptidase was identified in human serum. The serum enzyme crossreacted with an antiserum to the rabbit kidney metalloendopeptidase, thereby suggesting that the two enzymes have common antigenic determinants.;Serum metalloendopeptidase activity was measured in 150 controls and in 95 sarcoidosis patients. The mean enzyme activity in the sarcoidosis group was more than 3-fold higher than that of the controls (p < 0.001). Highest activities were found in patients whose chest roentgenograms showed hilar lymphadenopathy and interstitial infiltrates. Enzyme activity in patients with active tuberculosis, pulmonary neoplasms, and interstitial pulmonary fibrosis did not differ significantly from that of controls.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Biomedical Sciences
