The properties of glucose-6-phosphate dehydrogenase and its conjugates with progesterone in aqueous and micellar media

A. N. Eryomin, E. I. Karasyova

Institute of Bioorganic Chemistry, Academy of Sciences of the Byelorussian SSR

Abstract: Effects of the composition of the glucose-6-phosphate dehydrogenase conjugates with progesterone (E-PRG) on their activity, thermostability and interaction with antibodies against progesterone (Anti-PR G) in water and reversed micelles of Aerosol OT and Triton X-45 in heptane were kinetically studied. It is shown that dimethylformamide is an optimal additive to the buffered solutions at the enzyme modification by progesterone. The activity and thermostability of the modified enzyme decreases as compared with the initial enzyme.

Unlike the rate constants of the native enzyme inactivation, their values for the enzyme conjugates increase with the growth of the protein concentration up to 0.2 mg/ml.

The catalytic activity of conjugates, containing 15 molecules of progesterone per an enzyme molecule, increases in the presence of antiserum against progesterone whereas the activity of the enzyme conjugates, containing 20 or 45 steroid molecules, is effectively inhibited by Anti-PRG. The efficiency of Anti-PRG inhibiting action and of the thermoinactivation alteractions for the conjugate E-PRG-20 in the reversed micelles of surfactants increases as compared with that in buffered solutions. Free progesterone in the micelles affects the E-PRG-20 interaction with the specific antiserum.

Russian Journal of Bioorganic Chemistry 1991, 17 (5):610-617

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