Open AccessIsolation of a psychrotrophic Azospirillum sp. and characterization of its extracellular protease
Author(s) -
Oh KunHee,
Seong Chang Soo,
Lee Soo Woong,
Kwon OSeob,
Park Young Shik
Publication year - 1999
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1999.tb13565.x
Subject(s) - protease , iodoacetamide , biochemistry , proteases , molecular mass , extracellular , enzyme , pmsf , bacteria , chemistry , cysteine protease , biology , pepstatin , microbiology and biotechnology , cysteine , genetics
Abstract A novel psychrotrophic bacterium secreting a protease was isolated from a mountain soil in Korea. On the basis of a 16S rDNA sequence analysis and physiological properties, the isolate was identified as an Azospirillum sp. The protease purified from the culture supernatant was a monomer in its native form with an apparent molecular mass of 48.6 kDa on SDS‐PAGE. The protease was active in a broad pH range around 8.5 and at temperatures up to 40°C and stable at temperatures below 30°C for 3 days. The proteolytic activity was inhibited by iodoacetamide and EDTA. The Mg 2+ ion did not activate the enzyme much but reversed the inhibition by EDTA, suggesting that the protease belongs to a cysteine protease stabilized by the Mg 2+ ion.