Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.3.5.1 (succinate dehydrogenase)
 8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of unilateral nephrectomy (UN) and streptozotocin (STZ) diabetes on the activities of enzymes involved in uridine and cytidine synthesis in early renal growth (3-14 days after stimulus to growth) have been compared. Measurements were also made of glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) and of glucose 6-phosphate (G6P), UDP-glucose, and glycogen, in relation to phosphoribosyl pyrophosphate, ribonucleotide, and complex carbohydrate formation. There were striking differences in the activities of CTP synthetase, G6PDH, and 6PGDH in the two conditions, with a three-fold increase in all three enzymes at 3 and 5 days and a two-fold increase above basal values at 14 days of STZ diabetes. The UN group showed no significant change in CTP synthetase at any stage and the activity of G6PDH and 6PGDH only kept pace with renal growth. Changes in routes of uridine synthesis were less marked, with a more rapid rise in carbamoyl-phosphate synthetase (glutamine) and a lesser response of dihydroorotate dehydrogenase in the UN relative to the STZ-diabetic groups. The enzymes of complex II and of uracil phosphoribosyltransferase showed essentially similar patterns during renal hypertrophy in UN and STZ diabetes. The parallel increase in CTP synthetase, G6PDH, and 6PGDH in the kidney in diabetes, also known to increase in growth situations in hepatomas and in renal tumors, is discussed in relation to hormone signals involved in renal growth. The importance of the concentration of CTP, and thus of CTP synthetase, in the CTP-cytidyltransferase reaction, an enzyme with a high Km for CTP, makes the present observation of the striking increase in CTP synthetase in STZ diabetes of particular interest in relation to phosphatidylcholine formation and hormone signal transduction.
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PMID:Uridine and cytidine nucleotide synthesis in renal hypertrophy: biochemical differences in response to the growth stimulus of diabetes and unilateral nephrectomy. 138 Dec

A particulate fraction consisting of heavy organelles such as nuclei and mitochondria was prepared from Ehrlich ascites tumor cells. From this fraction we have purified a GTP-binding protein with a molecular mass of 33 kDa (MTG33) by guanidine hydrochloride extraction followed by four steps of column chromatography. The Kd value of MTG33 for GTP was 17 nM. [alpha-32P]GTP-binding to MTG33 was inhibited by GTP and GDP, but not appreciably by ATP, CTP, UTP, or GMP. MTG33 hydrolyzed GTP to GDP at a rate of 4.5 mmol/min/mol protein. Subcellular fractionation analysis of mouse liver revealed that the heavy mitochondrial fraction contained the highest level of MTG33. Furthermore, dual immunofluorescence examination indicated that the staining of NIH 3T3 cells with anti-MTG33 antibody is coincident with the distribution of mitochondrial succinate dehydrogenase. Of the mouse organs examined, the heart contained the highest level of MTG33. These results strongly suggest that MTG33 is a GTP-binding protein located in mitochondria.
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PMID:Purification of a GTP-binding protein localized in mitochondria. 811 21