Isolation of a cadmium-releasing bacterium and characterization of its novel protease.
Microorganisms were screened for their ability to release cadmium from scallop hepatopancreas, which is the main residue after removing of the edible parts of scallop. The isolated strain, 23-0-11, identified as Arthrobacter nicotinovorans, secreted a protease which released cadmium from scallop hepatopancreas into the liquid medium. The molecular mass of the enzyme was estimated to be 27 kDa. The sequence of the 15 N-terminal amino acids of the protease showed no close similarity with any other protein. Compared with a commercial enzyme, the purified protease had greater ability to release cadmium. The enzyme activity was greatest at 50 degrees C and pH 7.0, and was enhanced in the presence of Ca(2+), Mg(2+) and Mn(2+), while being strongly inhibited by Co(2+). The inhibition profile by the serine protease inhibitor, phenylmethylsulphonyl fluoride (PMSF), confirmed that the protease belonged to the serine protease family.
Laboratory of Applied Microbiology, Graduate School of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo 060-8589, Japan.
Shukun
S
Ren
Fusao
F
Tomita
Atsushi
A
Yokota
Kozo
K
Asano
D000818:Animals; D001173:Arthrobacter / Q000201:enzymology*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002104:Cadmium / Q000378:metabolism*; D002413:Cations, Divalent / Q000378:metabolism*; D043143:Hepatopancreas / Q000201:enzymology; D008974:Mollusca / Q000201:enzymology; D010447:Peptide Hydrolases / Q000378:metabolism*; D010664:Phenylmethylsulfonyl Fluoride / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology
D001426:Bacterial Proteins; D002413:Cations, Divalent; D011480:Protease Inhibitors; D002104:Cadmium; D010664:Phenylmethylsulfonyl Fluoride; D010447:Peptide Hydrolases