AMINOPEPTIDASE ACTIVITY OF AN ANTITUMOR ANTIBIOTIC, C-1027

• Published in: Journal of antibiotics Vol. 45; no. 1; pp. 113 - 117
• Main Authors: SAKATA, NOBUO, TSUCHIYA, KAYOKO S., MORIYA, YUKARI, HAYASHI, HIDEMI, HORI, MAKOTO, OTANI, TOSHIO, NAGAI, MACHIKO, AOYAGI, TAKAAKI
• Format: Journal Article
• Language: English
• Published: Tokyo JAPAN ANTIBIOTICS RESEARCH ASSOCIATION 01.01.1992; Japan Antibiotics Research Association
• Subjects: Aminoglycosides; Aminopeptidases - antagonists & inhibitors; Aminopeptidases - metabolism; Aminopeptidases - radiation effects; Animals; Anti-Bacterial Agents - pharmacology; Antibiotics, Antineoplastic - antagonists & inhibitors; Antibiotics, Antineoplastic - chemistry; Antibiotics, Antineoplastic - metabolism; Antibiotics, Antineoplastic - radiation effects; Antineoplastic agents; Apoproteins - metabolism; Biological and medical sciences; Carcinoma, Ehrlich Tumor; Cell Survival - drug effects; DNA, Neoplasm - drug effects; Enediynes; General aspects; Leucine - analogs & derivatives; Leucine - pharmacology; Leupeptins - pharmacology; Medical sciences; Microsomes - enzymology; Oligopeptides - pharmacology; Peptides; Pharmacology. Drug treatments; Proteins - antagonists & inhibitors; Proteins - chemistry; Proteins - metabolism; Proteins - radiation effects; Substrate Specificity; Swine; Tumor Cells, Cultured; Ultraviolet Rays; Antineoplastic agent; Enzyme; Enzyme inhibitor; Cytotoxicity; In vitro; Antibiotic; Enzymatic activity; Apoproteins; Ehrlich ascites tumor; Aminopeptidase; Mechanism of action; Tumor cell; Chromophore
• ISSN: 0021-8820; 1881-1469
• DOI: 10.7164/antibiotics.45.113

An antitumor antibiotic C-1027, a complex protein consisting of an apoprotein and a non-covalently bound chromophore, showed some aminopeptidase activity, 1/15 (on the basis of activity per mg protein) that of porcine kidney enzyme [E.C. 3.4.11.2] by use of L-phenylalanyl 4-methyl-coumaryl-7-amide as the substrate. Neither the apoprotein alone nor the chromophore alone were active. Amastatin and bestatin but not leupeptin inhibited the activity. The enzyme activity of the holo-antibiotic, as opposed to that of the porcine kidney enzyme, was readily lost by UV irradiation, indicating that the intact structure of the chromophore was needed to maintain the native conformation of the holo-antibiotic. The cytotoxicity of the holo-antibiotic, but not that of the chromophore, to Ehrlich carcinoma cells in vitro was reduced to 1/5 by 1 μg/ml of amastatin which alone had no effect on cell growth. The porcine aminopeptidase was not cytotoxic at all even at higher concentrations (higher enzyme activities/ml). Amastatin possibly occupied the catalytic domain of the holo-antibiotic, interfering with the binding of the holo-antibiotic with some cell-surface protein(s). Amastatin did not inhibit the holo-antibiotic to cleave isolated DNA.