Abstract
Lysozyme was measured using the synthetic substrate 3′,4-dinitrophenyl tetra-N-acetyl-β-chitotetraoside and the LKB Reaction Rate Analyser. This method has been evaluated by comparing levels obtained with serum samples from healthy individuals and patients with either cancer or inflammatory bowel disease with those obtained from the same specimens using a turbidimetric method. In terms of standard egg-white lysozyme, the colorimetric method gave much higher levels for all samples than the turbidimetric method; however, similar group differences were maintained. For individual serum specimens significant correlation between the two methods was found to occur only in the healthy group. Assay precision for the two methods was similar but the turbidimetric method could detect levels of lysozyme activity which were 10 times lower than those detected by the colorimetric method.