Oxidation of compounds metabolized through folate coenzyme pathways in vitamin B12-deficient rats |
| |
Authors: | Virginia Brothers Barbara ONeill Rowley Theo Gerritsen |
| |
Institution: | Departments of Pediatrics and Physiological Chemistry, Waisman Center on Mental Retardation and Human Development, University of Wisconsin Center for Health Sciences, Madison, Wisconsin 53706 USA |
| |
Abstract: | The effects of vitamin B12 deficiency in rats and dietary supplementation with vitamin B12 and/or l-methionine plus folate on the oxidation of compounds metabolized through folate coenzyme pathways were investigated. Rats fed a vitamin B12-deficient diet oxidized significantly lower amounts in 60 min of l-histidine, glycine, sarcosine, formate, and l-serine to CO2 than vitamin B12-supplemented controls. Supplementation of the deficient diet with l-methionine plus folate restored the ability to oxidize the ring-2-carbon of l-histidine, the methyl group of sarcosine, and formate to the same level as that observed in animals receiving vitamin B12. In contrast, oxidation of the 1-carbon of glycine and the 3-carbon of l-serine was not restored to control levels by addition of methionine plus folate to the vitamin B12-deficient diet. Inhibition of the metabolism of the 2-carbon of glycine to CO2 was partially overcome by additional dietary methionine and folate. Glycine synthase activity in homogenates paralleled the in vivo pattern of oxidation of the 1-carbon of glycine to CO2, whereas sarcosine dehydrogenase activity appeared to increase 2-fold in vitamin B12 deficiency. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|