title: Purification and properties of a proteinaceous metallo-proteinase inhibitor from Streptomyces nigrescens TK-23.
abstract: A novel metallo-proteinase inhibitor which is capable of inhibiting the activities of metallo-proteinases such as the thermolysin, was isolated from the culture filtrates of Streptomyces nigrescens TK-23. The inhibitor was purified batch-wise from the culture filtrate by Amberlite IRC-50 and column chromatographies on CM-Sephadex C-50 and Sephadex G-50. The purified inhibitor showed a single band on 15% polyacrylamide gel electrophoresis at pH 4.3, and at pH 7.5 on SDS-gels. The inhibitor retained 80% of its original activity after treatment of 100 degrees C for 5 min between pH and 7. The molecular weight was estimated to be 12 000 by gel filtration and SDS-polyacrylamide gel electrophoresis, and calcuated as 11 950 from its amino acid composition. The isoelectric point was pH 10.3. The inhibitor showed a high content of hydrophobic amino acids, did not contain tryptophan, and had two disulfide bridges. It also showed specific inhibitory activity for metallo-proteinases but not for serine-, thio- and carboxyl-proteinases.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing; D008667:Metalloproteins / Q000378:metabolism*; D008970:Molecular Weight; D011480:Protease Inhibitors / Q000302:isolation & purification*; D013302:Streptomyces / Q000378:metabolism*; D013379:Substrate Specificity; D013820:Thermolysin / Q000037:antagonists & inhibitors*
chemical_list: D000596:Amino Acids; D008667:Metalloproteins; D011480:Protease Inhibitors; D013820:Thermolysin