ENZYMATIC DETERMINATION OF ANTI-NAD+ GLYCOHYDROLASE IN SERUM

A colorimetric method for measuring anti-NAD+ glycohydrolase in human sera has been developed. The assay involves the inhibition of NAD+ gly cohydrolase (EC 3.2.2.5) by the antibody and determination at the noni nhibited enzyme activity by using an enzymatic amplifying system for N AD+. The assay is easily carried out and has the additional advantage of a direct relationship between signal and antibody concentration. Th e results obtained for 100 human sera compare favorably with other tes ts commonly used to obtain evidence of streptococcal infections or the ir complications, such as the anti-streptolysin O and the anti-DNase B tests.