[1H-NMR-spectroscopic evidence for the release of N-acetyl-alpha-D-neuraminic acid as the first product of neuraminidase action (author's transl)].

The 1H-NMR spectroscopy was used to study the anomeric configuration of N-acetyl-D-neuraminic acid released by the action of neuraminidase. The hydrolysis of NeuAcalpha 2 leads to 3 Gal-beta 1 leads to 4Glc (20mM) by the enzymes of Clostridium perfringens and Arthrobacter ureafaciens (50 mU, 150 mU and 800 mU, respectively) in 50mM Na/K-phosphate buffer pD 5.4 was observed by recording the spectra. On the basis of the characteristic signals of the protons at C-3 (alphaNeuAc: delta[H(3e)] = 2.72, delta[H(3a)] = 1.64; betaNeuAc: delta[H(3e)] = 2.25, delta[H(3a)] = 1.84) the product of the enzymatic cleavage was identified to be the N-acetylneuraminic acid in the alpha-anomeric form. Two hypotheses are discussed to explain how the enzymatic hydrolysis may occur and how N-acetyl-alpha-D-neuraminic acid leaves the catalytic site of the neuraminidases with retention of the C-2 configuration.