Extracellular proteolytic activity of Aeromonas hydrophila complex.

Abstract

A simple quantitative plate assay was used to study the proteolytic activity of Aeromonas hydrophila complex. All the A. hydrophila complex strains hydrolyzed albumin, casein, and fibrinogen; most of the strains also digested gelatin (99.9 %), hemoglobin (94.3%), and elastin (73.2 %). None of the strains hydrolyzed collagen. The activity on each substrate varied from isolate to isolate. By using correlation analysis a close relationship was obtained among these proteolytic reactions, especially with albumin, casein, fibrinogen, gelatin, and hemoglobin hydrolysis. The elastin hydrolysis demonstrated a lower correlation with the other 5 proteolytic activities and implied a different enzymatic system. A higher casein and elastin hydrolytic response was found in the strains derived from human, fish, and other animal sources than those from water environments.