Quantitation of hyaluronidases by the Morgan-Elson reaction : comparison of the enzyme activities in the plasma of tumor patients and healthy volunteers

Abstract The Morgan–Elson reaction, a method for the determination of hyaluronidase activity, was optimized for the quantitation of the enzyme in biological material. Based on HPLC and spectrometric (UV-Vis, LC-MS) studies, the structure of the red-colored product (mesomeric forms of N 3 -protonated 3-acetylimino-2-(4-dimethylaminophenyl)methylidene-5-(1,2-dihydroxyethyl)furane) formed by condensation of chromogen III with p -dimethylaminobenzaldehyde is proposed. Activities corresponding to ≥0.1 IU of endogenous and therapeutically administered hyaluronidase can be detected in 50 μ l samples. Application of the method for the determination of the enzyme in plasma of tumor patients revealed no difference in activity levels, interindividual variability and pH profile compared to healthy volunteers.