結核菌培養濾液中よりのMycobacterial Lipase Inhibitorの分離ならびに性状

抄録

Production of mycobacterial lipase inhibitor (MLI) in the unheated culture filtrate of Mycobacterium tuberculosis H37Rv and its purification and characterization were studied.
The activity of MLI against lipase prepared from guinea pig peritoneal macrophages was measured fluorimetrically. Production of MLI reached the maximum level six weeks after incubation at 37°C on a modified Sauton liquid medium. Purification of MLI was performed by successive procedures with ammonium sulfate saturation, ion-exchange chromatography and gel filtrations. Four MLIs (MIA-1, 2, 3 and 4) were finally isolated. The molecular weights were estimated to be 150, 000, 62, 000, 29, 000 and 600, 000, respectively, by gel filtration on a Sephacryl S-300 column. All the MLIs were resistant to heating at 100 for 20min in boiling water, to treatment with butanol or Streptomycin, whereas they were sensitive to proteolytic enzymes such as trypsin, pronase and protease. The results obtained from gel filtration on a Sephadex G-200 column and preliminary SDS-polyacrylamide gel disc electrophoresis strongly support the idea that some of these MLIs would be aggregates composed of similar poly peptides.
The activity of MLIs against lipase from guinea pig peritoneal macrophages was more pronounced when 4-methylumbelliferyl (4-MU)-oleate was used as a substrate than 4-MU palmitate or 4-MU-elaidate as a substrate. MLIs acted little against lipase preparations from human peripheral blood leukocytes, guinea pig polymorphonuclear leukocytes and mouse peritoneal macrophages, and none of other lysosomal acid hydrolases such as acid phosphatase, β -glucuronidase, N-Ac-β-glucosaminidase and N-Ac-β-galactosaminidase prepared from guinea pig peritoneal macrophages.