Studies on the lipase of Chromobacterium viscosum. V. Physical and chemical properties of the lipases.

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Abstract
Physical and chemical properties of the 2 kinds of lipases [EC 3.1.1.3] (lipase A and lipase B) from C. viscosum were investigated. Sedimentation constants were 5.35 .times. 10-13 and 3.82 .times. 10-13 cm .cntdot. g/s .cntdot. dyne; MW were 1.2 .times. 105 and 2.7 .times. 104; intrinsic viscosities were 0.060 and 0.051 dl/g; partial specific volumes were 0.816 and 0.663 cm3/g; isoelectric points were 4.7 and 6.9 for the lipase A and B, respectively. From the study of ORD [optical rotatory dispersion], the .alpha.-helix content of the lipase A was calculated to be < 10% and of that the lipase B was about 20%. The amino acid compositions of the lipases were different from each other and the lipase B did not contain cystine. Lipid was not detected in either enzyme and carbohydrate was found only in lipase A (14%). The modification of histidine residue with diazonium-1-H-tetrazole resulted in a decrease in the enzymic activities. The histidine residue in the lipase B was probably related to the catalytic action of the enzyme. Some properties of the lipases concerned with the affinity of the enzymes on their hydrophobic substrates were also discussed.