API-2b, a New Alkaline Protease Inhibitor Produced byStreptomyces griseoincarnatusStrain No. KTo-250

Purification of API-2 Degrading Protease fromStreptomyces griseoincarnatusStrain No. KTo-250, an API-2 Producer

“…AP-J!-3) or API-2b 4 ) and API-2c 5 ) used in this work were prepared from culture filtrate of Streptomyces pselldogriseollls strain No. KTo-332 or Streptomyces griseoincarnatlls strain No.…”

Partial Amino Acid Sequence of an Alkaline Protease Inhibitor, API-2 (b and c)

“…KTo-250, the producer of API-2b and API-2c. 1 ) We also reported that Met-Ile bond located within a disulfide bridge in the API-2 molecule is the reactive site for the inhibition of subtilisin BPN'. 7 ) It is clear from the results of this experiment that the peptide bond, Met-Ile, located between residues 74 and 75 of API-2b.…”

Modification of API-2c and Its Reactive Site

“…API-2b 1 ) and API-2c 2 ) isolated from the culture filtrate of Streptomyces griseoincarnatus strain No, KTo-250 inhibit microbial alkaline proteases such as subtilisin BPN' and Sfericase, but not serine proteases, metal proteases, thiol proteases, or acid proteases, The numbers of amino acid residues of API -2b and API-2c are 117 and 111, respectively. Both inhibitors are characteristic in that they contain an isoleucine residue in each molecule.…”