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Alkaline serine protease produced from citric acid by Bacillus alcalophilus subsp. halodurans KP 1239
Y Takii1, N Kuriyama, Y Suzuki
1Department of Agricultural Chemistry, Kyoto Prefectural University, Japan.
Abstract:
Maximum production of alkaline serine protease by Bacillus alcalophilus subsp. halodurans KP 1239 was achieved after 24 h cultivation, at an initial pH of 7.6, on a medium containing 1.0% sodium citrate, 0.3% yeast extract, and 0.3% KH2PO4. The enzyme was purified to crystalline form from culture broth. The enzyme was most active at 60 degrees C and at pH 11.5. The molecular weight, isoelectric point and sedimentation coefficient in water at 20 degrees C were estimated as 29,000, 8.8 and 3.3S, respectively. The N-terminal amino acid sequence was Ala-Gln-Ser-Val-Pro-Trp-Gly-Ile-Ser-Arg-Val-Gln-Ala-Pro-Ala-Ala- His-Asn-Arg-Gly-. The enzyme shared its antigenic determinants with B. alcalophilus ATCC 21522 serine protease, but not with the subtilisins Carlsberg and BPN'.