Sialyltransferase Activity in Normal and Atherosclerotic Human Aorta Intima

E. V. Gracheva^*, N. N. Samovilova, N. K. Golovanova, O. P. Il'inskaya, E. M. Tararak, and N. V. Prokazova

Institute of Experimental Cardiology, Cardiology Research Center, Russian Ministry of Health, 3-ya Cherepkovskaya ul. 15a, Moscow, 121552 Russia; fax: (095) 415-2962; E-mail: gracheva@cardio.ru

^* To whom correspondence should be addressed.

Received June 26, 2000; Revision received October 16, 2000

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Sialyltransferase activity has been determined in Golgi membrane fractions isolated from atherosclerotic and normal intima of human aorta by measuring the transfer of N-acetylneuraminic acid (NeuAc) from CMP-NeuAc to asialofetuin. The asialofetuin-sialyltransferase activity was found to be twofold higher in the atherosclerotic intima than in the normal intima. The mean value of the apparent Michaelis constant (K_m) for the sialylating enzyme in both tissues did not differ and was 57 µM. In contrast, the maximal velocity (V_max) was 2-fold higher for the atherosclerotic intima than for the normal intima. These results suggest that expression of asialofetuin-sialyltransferases of the aortal intima may be increased in atherosclerosis.

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KEY WORDS: sialyltransferase activity, human aorta intima, Golgi membrane fractions, atherosclerosis

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