Measurement of hyaluronidase activity in normal human serum

A detailed evaluation of the assay for serum hyaluronidase (HAE) activity originally developed by Bonner and Cantey [W.M. Bonner, Jr. and E.Y. Cantey, Clin. Chim. Acta, 13 (1966) 746-752] is described, together with studies of its precision. The method is based on the liberation of saccharides with N-acetylglucosamine (NAG) end-groups from hyaluronic acid. The NAG is quantitated by heating with alkaline tetraborate to form an intermediate which reacts with p-dimethylaminobenzaldehyde in acidic medium to form a coloured product. The optimised assay, which requires less that 50 microliters of serum, was used to study the HAE activity of 70 normal sera. The mean HAE activity was 17.1 mumol NAG min-1 l-1 (range 11.5-27.0 mumol NAG min-1 l-1); there was no significant difference with age (t = 1.65, 0.5 > P > 0.1) or sex (t = 0.33, P > 0.5).