Purification and characterization of an extracellular low temperature-active and alkaline stable peptidase from psychrotrophic Acinetobacter sp MN 12 MTCC (10786).

Abstract

An extracellular low temperature-active alkaline stable peptidase from Acinetobacter sp. MN 12 was purified to homogeneity with a purification fold of 9.8. The enzyme exhibited specific activity of 6,540 U/mg protein, with an apparent molecular weight of 35 kDa. The purified enzyme was active over broad range of temperature from 4 to 60 C with optimum activity at 40 C. The enzyme retained more than 75 % of activity over a broad range of pH (7.0–11.0) with optimum activity at pH 9.0. The purified peptidase was strongly inhibited by phenylmethylsulfonyl fluoride, giving an indication of serine type. The Km and Vmax for casein and gelatin were 0.3529, 2.03 mg/ml and 294.11, 384.61 lg/ml/min respectively. The peptidase was compatible with surfactants, oxidizing agents and commercial detergents, and effectively removed dried blood stains on cotton fabrics at low temperature ranging from 15 to 35 C.