Synthesis of 2,6-anhydro-S-[ethylmercury(II)]-1-thio-D-glycero-L-manno-heptitol+ ++ and bis(2,6-anhydro-1-thio-D-glycero-L-manno-heptitol)mercury(II), and the study of their interaction with beta-D-galactosidase from E. coli.

Two competitive inhibitors of beta-D-galactosidase activity, namely, 2,6-anhydro-S-[ethylmercury(II)]-1-thio-D-glycero-L-manno-heptitol (4) and bis(2,6-anhydro-1-thio-D-glycero-L-manno-heptitol)mercury(II) (6), with inhibition constants of 8.0 X 10(-4) M and 1.9 X 10(-4) M, were synthesized. Compound 6 was incorporated into the crystalline enzyme by cocrystallization. The stoichiometry of the enzyme-inhibitor complex was 1:4, corresponding to one molecule of inhibitor per active site of the enzyme. Compound 4 was found to be unstable against X-ray irradiation, whereas compound 6 was submitted to X-rays for several days without any radiation damage.