(194aj) N-acetylchitohexaose Producing Chitinase Identified from Chitinase Profiles of Aeromonas schubertii by Enzymomics, a Novel Technique

Chitin, the abundant polysaccharide and main solid waste in the seafood processing industry, is mainly obtained from crustaceans now. Derivatives of chitin, inclusive of polysaccharides, oligosaccharides and monosaccharides, are biodegradable, histocmpatible and nontoxic. It attracts lots of attention since the chitin-oligosaccharides have been found to enhance the functions of immunological system and they might display as tumoricidal agents. While, the biological activity of chitin-oligosaccharides depends on the solubility and polymerization. The N-acetylchitohexaose with strong biological medical function has been demonstrated.

Chitinases are the enzyme cleaving chitin and distributed wildly. The chitinases in plants are part of defence as pathogenesis-related (PR) proteins. Few chitinases or chitinase-like proteins are identified in mammalian. Most functions of them are still unclear. In insects, crustaceans, and arachnids, chitin are the exoskeletons. Their chitinases play the roles in developing. In microorganisms with chitinases, those enzymes are essential for nutrients. For facilitate the chitin assimilation, many bacteria produce multiple types of chitinase with different biochemistry characteristics, such as molecule weights and pI. This multiplicity is presumed from different genes or modification of post-transcription and post-translation. Until now, the whole chitinases from one livestock have never profiled.

Recently, a technique, enzymomics, consolidating proteomics and zymography, in gel-activity assay, was developed. Enzymomics is the investigation of enzymome, the set of specific enzymes encoded by the genome. The approach was applied on a micoorganis, Aeromonas schubertii from the soil of mangroves marsh of south Taiwan. A bunch of the chitinases of A. schubertii were screened and profiled by enzymomics. Among those enzymes, one secretory chitinases with potent and SDS-resistant chitinolytic acititiy was selected and then isolated. This chitinsase was characterized with the molecular weight of 61,202 and produces hexameric oligochitinosaccharide from chitin degradation. It shows this enzyme has great potentialities for mass production of N-acetylchitohexaose in industry.