A SOLUBLE, DYE-LABELED CHITIN DERIVATIVE ADAPTED FOR THE ASSAY OF KRILL CHITINASE

1. Carboxymethyl-Chitin-Remazol Brilliant Violet (CM-Chitin-RBV) was used for a colorimetric assay of chitinase activity in Antarctic krill, Euphausia superba. Comparison with a reductimetric method by end-product detection was carried out by measuring FPLC elution profiles of krill crude extracts with both assays. Both profiles matched significantly. 2. Krill chitinase was highly specific to CM-Chitin-RBV. The assay was characterized by easy handling and a very high sensitivity compared to that of end-product detection. Hydrolysis of CM-Chitin-RBV by N-acetyl-beta-D-glucosaminidase, beta-glucosidase, beta-galactosidase and N-acteyl-muraminidase was negligible. 3. The enzyme characteristics of chitinase from Antarctic krill using CM-Chitin-RBV were: pH(opt) = 7.5, T(opt) = 50-55-degrees-C, E(a) = 52.1 kJ . mole-1, K(M) = 0.07 +/- 0.01 mg . ml-1.