A novel proteinaceous Kex 2 proteinase inhibitor, kexstatin, from Streptomyces platensis Q268.
We found a novel proteinaceous Kex 2 proteinase inhibitor, named kexstatin, in the culture supernatant of Streptomyces platensis Q268. The purified kexstatin was homogeneous by SDS-PAGE and the molecular weight was estimated to be 13,000. The N-terminal amino acid sequence of kexstatin has high similarity to Streptomyces subtilisin inhibitor (SSI), suggesting that kexstatin belongs to the SSI family. Kexstatin was a strong inhibitor of Kex 2 proteinase and subtilisin but not thermolysin, trypsin, or chymotrypsin. The IC50 value of kexstatin against 1 microgram of Kex 2 proteinase was 1.4 micrograms.
Oda
K
K
Department of Applied Biology, Faculty of Textile Science, Kyoto Institute of Technology, Japan.
Takahashi
S
S
Kikuchi
N
N
Shibano
Y
Y
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D043484:Proprotein Convertases; D011480:Protease Inhibitors / Q000302:isolation & purification*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013302:Streptomyces / Q000737:chemistry*; D013381:Subtilisins / Q000037:antagonists & inhibitors*
D001426:Bacterial Proteins; D011480:Protease Inhibitors; D029701:Saccharomyces cerevisiae Proteins; D043484:Proprotein Convertases; D013381:Subtilisins; C058751:KEX2 protein, S cerevisiae