flavin-adenine-dinucleotide and Ascorbic-Acid-Deficiency

Ascorbic acid deficiency causes qualitative and quantitative differences in the guinea pig hepatic flavin-containing monooxygenase (FMO). Kinetic studies with purified FMO indicated no significant change in the apparent Km of dimethylaniline or NADPH in ascorbate-supplemented or -deficient animals. Following purification of ascorbate-deficient guinea pig FMO by DEAE-cellulose and blue agarose chromatography, exogenous FAD was required for 15% of the FMO microsomal activity recovered. In contrast, only 5% of the total microsomal enzyme recovered from ascorbate-supplemented animals required exogenous FAD. Furthermore, there was an enhanced sensitivity to time-dependent nonlinearity with the purified ascorbate-deficient guinea pig FMO. The degree of time-dependent nonlinearity was related to the concentration of substrate. Also, purified ascorbate-supplemented guinea pig FMO was stable for 4 weeks at -20 degrees, whereas the ascorbate-deficient enzyme was inactivated. A decrease in the quantity of ascorbate-deficient guinea pig FMO compared to ascorbate-supplemented was indicated by a marked reduction in total FMO activity recovered from blue agarose chromatography and reduced protein staining intensity with SDS-PAGE at 56,000 daltons.

Topics: Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Flavin-Adenine Dinucleotide; Guinea Pigs; Kinetics; Molecular Weight; Oxygenases

Topics: Animal Nutritional Physiological Phenomena; Animals; Ascorbic Acid Deficiency; Avitaminosis; Body Weight; Erythrocytes; Flavin-Adenine Dinucleotide; Folic Acid Deficiency; Glutathione Reductase; Guinea Pigs; Humans; Liver; Pyridoxine; Rats; Riboflavin; Riboflavin Deficiency; Thiamine Deficiency; Vitamin B 6 Deficiency; Vitamin B Deficiency