6533b872fe1ef96bd12d4150

RESEARCH PRODUCT

Control of the thermal reaction of a photochromic spirobenzopyran by the enzyme-like activity of albumins

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Abstract The thermal ring-opening reaction of a negative photochronic spirobenzopyran was investigated in the presence and absence of albumins. In the presence of the proteins, the formation of the merocyanine form from the spiro form is enhanced markedly by two orders of magnitude. The results for five different albumins indicate the enzyme-like activity of the proteins. The influence of pH, temperature and various ligands was examined in detail for bovine serum albumin (BSA) and human serum albumin (HSA). In particular, it was deduced that warfarin shows reversible purely competitive inhibition for BSA with an inhibitor constant K 1 of 1.6×10 −3 M. The results suggest that the catalytic centre for the reaction with the spirobenzopyran is different for BSA and HSA. Albumin can control the velocity of the thermal reaction of the photochromic system.