A DYED SUBSTRATE FOR THE ASSAY OF ENDO-1,4-BETA-GLUCANASES

A new dyed substrate was prepared for the rapid determination of endo- 1,4-beta-glucanases. Carboxymethylcellulose was coupled with Ruthenium red to obtain a violet powder, which was stable enough to allow for r eproducible assays. The spontaneous reaction is based on ionic interac tions between the negatively charged carboxymethylcellulose and the co mplex cation of the dye. The enzymic assay is based on spectrophotomet ric measurement at 535 nm of the enzyme-released dyed fragments with l ow-molecular-weight filterable through a 0.22 mu m filter. The release of coloured fragments from this dyed substrate was proportional to it s solubilization. The absorbance was directly proportional to the enzy me amount in the range 0.5-5.5 mU enzyme (A(535) = 0.1-0.95). This enz ymic assay is advantageous for both rapid time of analysis and sensiti vity.