Biocatalysis of isomerization of 1,2‐benzisoxazole by bovine serum albumin in an organic solvent

Abstract

The catalytic properties of bovine serum albumin (BSA) have been studied rather extensively. The protein has shown catalytic activities toward a variety of reactions in aqueous media. However, there appears to be no reports of reactions catalyzed exclusively in organic media. In this study, we report the catalytic property of BSA on the isomerization of 1,2-benzisoxazole in an organic solvent. Kinetics were performed using a continuous flow system in a spectrophotometer at 330 nm. The catalysis showed a Michaelis-Menten behavior with an estimated catalytic efficiency (k(cat)/K(M)) of 8.77 M(-1)S(-1). The influence of water content and inhibitors was also studied. The activity of BSA in acetonitrile is approximately 20% of that in water under similar conditions. Inhibition studies show that the active site may be the pyridoxal binding site involving Lys-220.

Supramolecular Phenylalanine-Derived Hydrogels for the Sustained Release of Functional Proteins

“…BSA has been reported to demonstrate esterase activity. − To measure Michaelis–Menten kinetics of our released BSA, we optimized an assay that monitors the hydrolysis of p -nitrophenyl acetate to p -nitrophenol by monitoring the increase in absorption at 401 nm every 0.4 s for 10 min of native or released BSA (10 μM) combined with serial dilutions of p -nitrophenyl acetate and plotted the resulting Michaelis–Menten plots (Figure D, see also Figure S15 in the Supporting Information) with V max (M min –1 ), K m (M), k cat (s –1 ), and catalytic efficiency ( k cat / K m , M –1 s –1 ) values outlined in Table . Released BSA was calculated to have a lower V max (2.83 × 10 –6 M min –1 ) than native BSA (4.84 × 10 –6 M min –1 ).…”