Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several NAD(P)(+)-dependent dehydrogenases were partially purified from Halobacterium halobium. When salt (2M (NH4)2SO4) was replaced with glycine betaine (4M or 6M), the zwitterion stabilised activity less completely than the salt. Nevertheless most of the enzyme activity still remained after 90h, e.g. 70% for malate dehydrogenase. This level of stabilisation permitted non-denaturing gel electrophoresis in 4M betaine after dialysis to replace salt. Coomassie Blue staining showed good separation of the proteins, and activity staining, hitherto impossible for halophilic enzymes, readily identified the individual dehydrogenase bands. Transfer of activity-stained gels to Coomassie staining solution halted background formazan staining and showed up activity and other protein bands in contrasting colours.
Biochem Mol Biol Int 1994 Jul
PMID:Activity staining of halophilic enzymes: substitution of salt with a zwitterion in non-denaturing electrophoresis. 798 66

The tertiary structure of Thermus aquaticus malate dehydrogenase (MDH) was predicted based on the known crystal structure of pig heart cytosolic MDH. Guanidinium chloride (GdmCl) unfolding experiments showed that there is only about a 4.2-kjoule/mol difference in delta G 0 between the pig and Thermus MDH. However, the two enzymes varied greatly in their [GdmCl]1/2, with Thermus MDH showing the expected increased stability (3.20 M against 0.58 M for pig MDH). The half-lives were determined for both Thermus MDH (34 min at 90 degrees C) and pig MDH (1.8 min at 60 degrees C). The Thermus MDH model was then examined to see what effect the substituted residues and changes may have on the enzyme, particularly in relation to its high thermal stability.
J Mol Graph 1994 Mar
PMID:An investigation of the thermal stabilities of two malate dehydrogenases by comparison of their three-dimensional structures. 801 96

The hypothalamic neuropeptide Y (NPY) system, along with levels of circulating corticosterone (CORT), were examined in rats at different times across the light/dark cycle. Tissue samples were taken from the mediobasal hypothalamus (MBH), which contains the primary hypothalamic NPY cell group of the arcuate nucleus (ARC), and the mediodorsal (MDH) hypothalamus, which contains the paraventricular and dorsomedial nuclei that receive a dense NPY innervation from the ARC. In these dissections, measurements of NPY mRNA and peptide levels were taken using a solution hybridization/nuclease protection assay procedure and radioimmunoassay. The results demonstrate that (i) NPY mRNA levels in the MBH, but not MDH, vary significantly in relation to the light/dark cycle, showing a sharp rise 4-6 h before dark onset, sustained high levels over the next 3-4 h and then, a sharp decline 1 h before dark onset; (ii) this rise in NPY mRNA in the MBH before dark onset, while associated with stable levels of MBH NPY during this time, is followed 2-4 h later, around dark onset, by a rise in NPY peptide levels of the MDH simultaneous to a decrease in NPY levels of the MBH; (iii) levels of circulating CORT shift dramatically across the light-dark cycle, exhibiting an increase from basal levels (< 0.3 microgram/dl) to 5 micrograms/dl approximately 4 h before dark onset, a further rise that peaks at 26 micrograms/dl around dark onset, and then a significant decline to 16 micrograms/dl at 2 h after dark onset; and (iv) there exists a positive relationship between CORT and NPY mRNA or peptide levels in the MBH during the 4-6 h before dark onset, while in the MDH, a positive relationship between this steroid and NPY peptide levels is obtained at dark onset. It is proposed that these rhythms, involving a predark rise in CORT and NPY gene expression leading to a peak in CORT and peptide levels at dark onset, are active in stimulating feeding behavior, particularly carbohydrate ingestion, which predominates at that time.
Mol Cell Neurosci 1994 Jun
PMID:Hypothalamic neuropeptide Y and its gene expression: relation to light/dark cycle and circulating corticosterone. 808 19

Thiolase is part of the fatty acid oxidation machinery which in plants is located within glyoxysomes or peroxisomes. In cucumber cotyledons, proteolytic modification of thiolase takes place during the transfer of the cytosolic precursor into glyoxysomes prior to the intraorganellar assembly of the mature enzyme. This was shown by size comparison of the in vitro synthesized precursor and the 45 kDa subunit of the homodimeric glyoxysomal form. We isolated a full-length cDNA clone encoding the 48,539 Da precursor of thiolase. This plant protein displayed 40% and 47% identity with the precursor of fungal peroxisomal thiolase and human peroxisomal thiolase, respectively. Compared to bacterial thiolases, the precursor of the plant enzyme was distinguished by an N-terminal extension of 34 amino acid residues. This putative targeting sequence of cucumber thiolase shows similarities with the cleavable presequences of rat peroxisomal thiolase and plant peroxisomal malate dehydrogenase.
Plant Mol Biol 1993 Apr
PMID:Thiolase mRNA translated in vitro yields a peptide with a putative N-terminal presequence. 809 65

Recent studies indicate that the mucosa of the urinary bladder may play a major role in the maintenance of normal bladder function. The mucosal surface of the urinary bladder serves as a protective layer against the irritative solutes found in the urine. The integrity of this barrier can be broken by overdistension, anoxia, detergents, alcohols, bacterial infection and by contact with agents to which the mucosa has been sensitized. In view that both anoxia and ischemia can mediate a breakdown in the role of the mucosal layer as a permeability barrier, it is reasonable to assume that this function is dependent on cellular metabolism. As an initial investigation we have compared a variety of biochemical and metabolic parameters between the mucosal layer (consisting of the lamina propria, urothelium, and any connective tissue and vascular tissue within this layer); and the muscularis layer. The results of these studies demonstrated that the rate of glucose metabolism to lactic acid (LA) of the mucosa was more than three-fold greater than that of the smooth muscle. The rate of CO2 production of the mucosa was 60% greater than that of the unstimulated smooth muscle. The maximal activity of the mitochondrial enzyme citrate synthase was significantly greater in the mucosa than in the smooth muscle, however, the activity of malate dehydrogenase was similar for both tissues. The maximal activity of the cytosolic enzyme creatine kinase was more than two-fold greater in the bladder smooth muscle than in the mucosa; although the affinities of the creatine kinase isoforms of the mucosa were significantly greater than those of the muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Cell Biochem 1993 Aug 11
PMID:Metabolic studies on rabbit bladder smooth muscle and mucosa. 826 70

The structure of malate dehydrogenase from Escherichia coli complexed with the substrate analog, citrate and the cofactor NAD, has been determined by X-ray crystallography. A monoclinic crystal of the malate dehydrogenase, grown in citrate buffer, was soaked in 10 mM NAD solution and found to be isomorphous with the apo-form. The X-ray data extended to 1.9 A, nearly the same resolution limit as the apo-enzyme crystals. The ternary complex of malate dehydrogenase has very few conformational differences from that of the pseudo binary complex of enzyme with bound citrate. In addition, the NAD molecule has a very similar conformation to the NAD as found in the crystal structure of the cytosolic eukaryotic malate dehydrogenase. Similar hydrogen bond interactions are made by both enzymes from polar groups belonging to the NAD. Such interactions include hydrogen bonds from the ribose oxygens and the phosphate oxygens, to backbone amide and carbonyl atoms of the protein and to side-chains of a select few conserved hydrophilic residues. The only notable difference occurs in the active site region where the nicotinamide moiety is obstructed from further entering the active site by the C-6 carbonyl atoms of citrate. In this position there are no direct polar interactions between the protein and the nicotinamide moiety. Energy minimization of the structure with malate substituted for citrate in the active site shows that the nicotinamide moiety assumes the same position in the active site as the NAD in cytosolic malate dehydrogenase. The carboxamide atoms of the energy minimized model make significant hydrogen bond interactions with the catalytic residue, H177, and with the main-chain atoms of I117 and V146 in the vicinity of the active site, while the position of the rest of the cofactor remains unchanged.
J Mol Biol 1993 Jul 05
PMID:Crystal structure of a ternary complex of Escherichia coli malate dehydrogenase citrate and NAD at 1.9 A resolution. 833 58

The specific activity of 17 beta-hydroxysteroid oxidoreductase (17-HOR) with estradiol-17 beta (E2), estrone (E1) and testosterone (T), as well as that of lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) were measured in homogenates of CF-1 mouse placenta during the latter half of pregnancy. 17-HOR activity with E2 and T increased over 100-fold between days 9 and 12, and 3- to 4-fold between days 15 and 19, with no further change to day 21. In contrast, activity with E1 increased 39-fold between days 9 and 12, 3.8-fold between days 15 and 19 but then decreased between days 19 and 21. The E2/T activity ratio was constant while the E2/E1 ratio increased between days 9 and 21. LDH increased 2-fold between days 9 and 12 with no further increase to day 19. MDH was constant from day 9 to 19. Activity with E2 was inhibited by T, 5 alpha-dihydrotestosterone (5 alpha-DHT) and DHA but not by E1, androstenedione (A) or 20 alpha-dihydroprogesterone. Activity with T was inhibited by E2, 5 alpha-DHT and DHA, but not by A. In contrast, activity with E1 was inhibited by A and DHA but not by E2, T or 5 alpha-DHT. The results suggest placental 17-HOR is developmentally regulated. Although the results are also suggestive of multiple forms of 17-HOR, a single enzyme with an ordered kinetic mechanism cannot be ruled out.
J Steroid Biochem Mol Biol 1993 Jul
PMID:Placental 17 beta-hydroxysteroid oxidoreductase, lactate dehydrogenase and malate dehydrogenase during the latter half of pregnancy in the mouse. 833 91

The activities of lactate dehydrogenase (LDH), malate dehydrogenase (MDH), and protein levels were measured in vitro incubation of tissue homogenate of brain and gonads with testosterone propionate (TP) in Channa punctatus (teleost). The activities of LDH and MDH were found to be highest in the ovarian tissues in comparison to the testis and the brain in control fish. TP (2 micrograms-4 micrograms/ml) stimulated testicular tissue with increases in LDH by 10-fold and MDH by 15-fold approximately, the ovary with significant increase in LDH and a decrease in MDH and the brain showed only an increase in MDH.
Biochem Mol Biol Int 1993 Jan
PMID:In vitro effect of testosterone propionate on lactate dehydrogenase and malate dehydrogenase in brain and gonads of Channa punctatus. 849 May 71

The levels of activity of some enzymes involved in oxidative metabolism have been determined in left ventricular tissue from spontaneously hypertensive rats compared with those in normotensive controls. Levels of pyruvate kinase were increased about 1.3 fold indicative of elevated glycolytic activity. Similarly, enhanced levels of lactate dehydrogenase were found, consistent with a requirement for increased oxidation of cytosolically-generated NADH. In addition a more active malate-aspartate shuttle, which in heart provides the major route for transfer of reducing equivalents to the mitochondria, was suggested by elevated levels of the cytosolic isoenzyme of aspartate aminotransferase; malate dehydrogenase did not increase but the activity of this enzyme is very high and unlikely to be rate-limiting in the shuttle. The levels of expression of mRNAs for three of these enzymes (pyruvate kinase, aspartate aminotransferase and malate dehydrogenase) were also determined and correlated well with the extent of change, if any, in the changes in enzymatic activity. Thus it seems that one response to development of hypertension in rats is an increase in expression of the genes for certain key enzymes involved in oxidative metabolism.
Biochem Mol Biol Int 1995 Nov
PMID:Changes in enzyme levels in hypertensive heart tissue. 862 6

Rabbit, pigeon and rat liver mitochondria convert exogenous phosphoenolpyruvate and acetylcarnitine to citrate at rates of 14, 74 and 8 nmol/15 min/mg protein. Citrate formation is dependent on exogenous HCO3-, is increased consistently by exogenous nucleotides (GDP, IDP, GTP, ADP, ATP) and inhibited strongly by 3-mercaptopicolinate and 1,2,3-benzenetricarboxylate. Citrate is not made from pyruvate alone or combined with acetylcarnitine. Pigeon and rat liver mitochondria make large amounts of citrate from exogenous succinate, suggesting the presence of an endogenous source of acetyl units or means of converting oxalacetate to acetyl units. Citrate synthesis from succinate by pigeon and rabbit mitochondria is increased significantly by exogenous acetylcarnitine. Pigeon and rat liver contain 80 and 15 times, respectively, more ATP:citrate lyase activity than does rabbit liver. Data suggest that mitochondrial phosphoenolpyruvate carboxykinase in vivo could convert glycolysis-derived phosphoenolpyruvate to oxalacetate that, with acetyl CoA, could form citrate for export to support cytosolic lipogenesis as an activator of acetyl CoA carboxylase, a carbon source via ATP:citrate lyase and NADPH via NADP:malate dehydrogenase or NADP:isocitrate dehydrogenase.
Comp Biochem Physiol B Biochem Mol Biol 1996 Aug
PMID:Synthesis of citrate from phosphoenolpyruvate and acetylcarnitine by mitochondria from rabbit, pigeon and rat liver: implications for lipogenesis. 884 May 17


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