BACTERIAL ALGINATE LYASE - ENZYMOLOGY, GENETICS AND APPLICATION

Alginate is a heteropolysaccharide comprised of mannuronate and guluro nate. Three different types of alginate-degrading enzymes, alginate ly ases A1-I, A1-II and A1-III, were produced by a bacterium isolated fro m a ditch. A1-I (63 kDa) was active on both brown seaweed (non-acetyla ted) and bacterial (acetylated) alginates, whereas A1-II (23 kDa) and A1-III (40 kDa) were specific to brown seaweed and bacterial alginates , respectively. The gene for A1-I was cloned, analyzed and a possible molecular route for the generation of A1-II and A1-III through post-tr anslational processing of A1-I was established. Novel physiological an d food technological functions of alginate were derived by depolymeriz ation of the polymer molecule. A pyrogen-free A1-III was massively pro duced by genetically engineered Gram-positive microbe.s and is conside red as a possible therapeutic agent for the treatment of patients with cystic fibrosis.