Location: Aquatic Animal Health ResearchTitle: Function of a recombinant Chitinase derived from a virulent Aeromonas hydrophila isolated from diseased channel catfish Author
Submitted to: American Fisheries Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/28/2015
Publication Date: 8/17/2015
Citation: Zhang, D., Xu, D. 2015. Function of a recombinant Chitinase derived from a virulent Aeromonas hydrophila isolated from diseased channel catfish [abstract]. American Fisheries Society. p. 145.
Technical Abstract: A chitinase was identified in extracellular products of a virulent Aeromonas hydrophila isolated from diseased channel catfish (Ictalurus punctatus). Bioactive recombinant chitinase (rChi-Ah) was produced in Escherichia coli. Purified rChi-Ah had optimal activity at temperature of 42°C and pH 6.5. The affinity (Km) for chitosan was 4.18 mg ml-1 with Vmax of 162 mg min-1 mg-1. With home-made colloidal chitin as substrate, rChi-Ah generated N,N’-diacetyl-glucosamine predominantly. Conversion of chitosan (is equal to or greater than 75% deacetylated) by rChi-Ah revealed five major products: 2 to 4 units of glucosamine, all of which had at least one acetyl group. It is postulated that N-acetylated glucosamine is the recognition and cleavage site of rChi-Ah; the minimal and maximal cleavages are two and four glucosamine units, respectively. Whether A. hydrophila benefits from the chitinolytic products for survival and/or infection merits further investigation. Additionally, since chitooligosaccharides have many interesting bioactivities, rChi-Ah is a useful chitinolytic enzyme for extensive research in related fields.