[Effects of polyols and sugars on the stability of microsomal cytochrome P-450].
A systematic study of the inhibiting effects of polyols, mono- and oligosaccharides, dextran and polyethyleneglycols on thermal inactivation of cytochrome P-450 in rabbit liver microsomes has been carried out. In a phosphate buffer (pH 6.6, 50 degrees) the stabilizing effect increases in the following order: glycol less than ramnose less than glucose less than sorbitol less than maltose less than xylose = = glycerol (15% vol.). The kinetics of thermal inactivation of the rabbit microsomal cytochrome P-450 have been studied within the temperature range of 45-54 degrees at increasing concentrations of glycerol. For all the temperatures studied in the absence and presence of glycerol the thermal inactivation of P-450 is characterized by two phases, the first being described by the first order constants. Glycerol lowers the rate of thermal inactivation of cytochrome P-450 as well as the activation parameters delta H* and delta S* of thermal inactivation. There exists a linear relationship between decreasing values of delta H* and delta S* and increasing concentrations of glycerol in the medium. The effects of polyols on the thermal inactivation of P-450 is discussed in terms of alteration of solvent and microsomal membrane structures.
D000438:Alcohols / Q000494:pharmacology*; D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004355:Drug Stability; D007700:Kinetics; D008862:Microsomes, Liver / Q000378:metabolism*; D009005:Monosaccharides / Q000494:pharmacology*; D011489:Protein Denaturation; D011817:Rabbits; D013329:Structure-Activity Relationship
D000438:Alcohols; D009005:Monosaccharides; D003577:Cytochrome P-450 Enzyme System
Vliianie poliolov i sakharov na stabil'nost' mikrosomal'nogo tsitokhroma P-450.