Purification, physico-chemical characterization and sequence of a heat labile alkaline metalloprotease isolated from a psychrophilic Pseudomonas species

The psychrophilic alkaline metalloprotease (PAP) produced by a Pseudomonas bacterium isolated from Antarctica has been purified and characterized. The gene encoding PAP has been cloned and sequenced and the derived amino acid sequence shows 66% identity with the mesophilic alkaline metalloprotease f rom Pseudomonas aeruginosa IFO 3455 (AP). Compared to the purified AP, PAP is three times more active at 20 degrees C, is very sensitive to chelating agents and is rapidly inactivated at 45 degrees C. The lower thermostabilit y of PAP can tentatively be explained by a loss of a stabilizing Ca2+, a de crease in the content of hydrophobic residues and a smaller aliphatic index . (C) 2000 Elsevier Science B.V. All rights reserved.