A HIGHLY DENATURANT-DURABLE ALGINATE LYASE FROM A MARINE BACTERIUM - PURIFICATION AND PROPERTIES

Poly(alpha-L-guluronate)lyase, which depolymerizes polyguluronate of a lginate, was purified from the culture medium of a marine bacterium is olated from the intestine contents of a red sea bream, Pagrus major. T he enzyme was homogeneous as judged by polyacrylamide gel electrophore sis in the presence and absence of SDS and the molecular weight of 42, 000 and 40,000 on SDS gel electrophoresis and on a Sephacryl S200HR co lumn chromatography, respectively. The activity of the enzyme was high er at around pH 8.5 and stable from pH 6-10. The active form of the en zyme, which has been thought to be once lost upon incubation of the en zyme at higher temperatures up to 80-degrees-C could be restored on co oling the enzyme. The residual activity was 45% even at 100-degrees-C. By treatment with other denaturants, the activity was maintained in 3 % SDS and was 70% in 6 M GHCl and 60% in 4 M urea on incubation at 25- degrees-C for 30 min. In addition, several chemical reagents were test ed for the relationship between the functional amino acid residue and the active form of the enzyme.