title: The influence of thiamine deficiency on porphyrin synthesis and porphyrin proteins.
abstract: 1. Studies carried out in cell-free rat-liver extracts showed an inhibitory effect of thiamine deficiency on porphyrin synthesis. 2. Extracts of normal and thiamine-deficient rat livers were incubated with the cofactors and substrates of the thiamine pyrophosphate-dependent enzyme, 2-oxoglutarate glyoxylate carboligase. There was a marked inhibition of porphyrin synthesis when the substances were added either individually or together. 3. Thiamine deficiency resulted in a decrease of haemoglobin concentration and catalase activity whereas a rise in tryptophanpyrrolase activity and cytochrome b5 and P450 concentration was observed.
mesh_terms: D000818:Animals; D002374:Catalase / Q000378:metabolism*; D002474:Cell-Free System; D002952:Citric Acid Cycle; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003580:Cytochromes / Q000378:metabolism; D004906:Erythrocyte Count; D005260:Female; D006038:Glyoxylates / Q000378:metabolism; D006400:Hematocrit; D006420:Hemeproteins / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism; D007655:Ketoglutarate Dehydrogenase Complex / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D011166:Porphyrins / Q000096:biosynthesis*; D051381:Rats; D013832:Thiamine Deficiency / Q000378:metabolism*; D014366:Tryptophan Oxygenase / Q000378:metabolism*
chemical_list: D003580:Cytochromes; D006038:Glyoxylates; D006420:Hemeproteins; D006454:Hemoglobins; D011166:Porphyrins; D003577:Cytochrome P-450 Enzyme System; D002374:Catalase; D014366:Tryptophan Oxygenase; D007655:Ketoglutarate Dehydrogenase Complex