Use of conjugates of bovine serum albumin with poly(alkylene oxide)s for solubilization of riboflavin ester.

Solubilization of 2',3',4',5'-tetrabenzoyl-5-acetyl-1,5-dihydroriboflavin (benzaflavin) by conjugates of BSA with poly(alkylene oxide)s [poly(ethylene glycol) and block co-polymers of ethylene oxide and propylene oxide (pluronics)] was investigated. Conjugates of BSA with pluronics were shown to have more solubilizing efficiency towards benzaflavin than BSA itself. Solubilized forms of benzaflavin are able to inhibit NADPH-dependent peroxidation of lipids in rat liver microsomes. A study of solubilized riboflavin ester transfer to mitochondria demonstrated that conjugates of BSA with pluronics may be advantageously employed for this purpose. Inhibitory properties of solubilized forms of benzaflavin were demonstrated by the study of their influence on the enzyme activity of D-amino-acid oxidase from pig kidney. The results show that solubilized forms of biologically active compounds based on conjugates of proteins with poly(alkylene oxide)s may be used for testing of chemical substances in biochemical systems.