Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.1.1.37 (malate dehydrogenase)
4,591 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The testicular stroma of the vampire bat including the testicular capsula and the lamina propria of the seminiferous tubuli, was strongly PAS-positive. This observation was a possible indication of great amounts of structural glycogen and other glycoconjugates at the level of smooth muscle cells; elongated contractile cells and/or collagen frameworks of the tunica albuginea and tubular lamina propria. In the last the basement membranes of the seminiferous tubules were particularly strongly PAS positive, as an indication of their neutral mucosubstances structural composition, previously described (Malmi et al., 1987). The epithelium lining from the cavitary and surface rete testis complex showed low reactivities to mucosubstances; total proteins and lipids and oxidative enzymes studied. Although the apical granulation at the rete testis epithelium showed an intense PAS reactivity with hypothesis of glycoprotein secretion, through the rete. The PAS, Sudan Black B, NADH, MDH and LDH reactions of the testicular interstitium seem correlate to steroid metabolism (biosynthesis and secretion), at the Leydig cells level. The seminiferous epithelium generally had low reactions to all the histochemical studies realized. Particularly in the adbasal compartment the histochemical localizations of NADH diaphorase and LDH were possible related to glycolytic activities and general carbohydrates metabolism, both enzymes, and hydrogen transport, the NADH. The strong PAS, diastase and PAS, and alcian blue pH 2.5 and PAS reactions observed in the adluminal seminiferous epithelium compartment were directly related to the spermatids acrosomal glycoconjugates structuration. Also the SDH localization at this level seems to be related to the mitochondrial activities at the middle piece level in the late spermatids.
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PMID:[Histochemical and structural characteristics of the testis of the vampire bat (Desmodus rotundus rotundus, Geoffrey, 1810)]. 208 86

A blotting method is described to detect enzymes that do not normally yield a colored product. The method can be used for dot blotting as well as blotting after gel electrophoresis of many enzymes if the reactions they catalyze can be coupled to an oxidase or a dehydrogenase. The latter, designated "auxiliary enzymes," are preimmobilized on membranes of nitrocellulose or positively charged nylon and the reaction they catalyze is coupled with reduction of tetrazolium salt to yield colored formazan on areas of the transfer membrane occupied by the blotted enzymes. In the examples reported here, preimmobilized glucose oxidase, L-amino acid oxidase, xanthine oxidase, malate dehydrogenase, and a mixture of hexokinase and glucose-6-phosphate dehydrogenase were used as auxiliary enzymes to detect blotted invertase, leucine aminopeptidase, purine nucleoside phosphorylase, fumarase, and adenylate kinase, respectively. Detection limits varied, but never exceeded 100 ng for these enzymes. After blotting from polyacrylamide gels, the fumarase assay was the most sensitive of those investigated, detecting 10 ng of enzyme used for electrophoresis. Invertase, a glycoprotein, was detected with higher sensitivity on nitrocellulose membranes when concanavalin A was present on the membrane in addition to the auxiliary enzyme, glucose oxidase. On blots from isoelectric focusing gels, the assay detected two isozymes of purine nucleoside phosphorylase in a sample from calf spleen and at least five isozymes of this enzyme in lysates from human red cells.
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PMID:Activity staining of blotted enzymes by reaction coupling with transfer membrane-immobilized auxiliary enzymes. 245 38

Dogs with naturally occurring aerobic or anaerobic bacterial overgrowth have been examined before and after antibiotic therapy in order to assess reversibility of damage to the jejunal mucosa. Histological changes in peroral jejunal biopsies were relatively minor before and after treatment, but sucrose density gradient centrifugation revealed specific biochemical abnormalities that responded to antibiotic therapy. Aerobic overgrowth was initially associated with a marked loss of the main brush border component of alkaline phosphatase activity; this recovered following treatment, suggesting that aerobic bacteria may cause reversible damage to the hydrophobic region of the brush border membrane. In contrast, anaerobic overgrowth was initially associated with a marked reduction in brush border density, indicative of a considerable fall in the glycoprotein-to-lipid ratio of the membrane. Density increased from 1.17 to 1.21 g/ml after antibiotic therapy, consistent with recovery from this relatively severe damage to the brush border caused by anaerobic bacteria. Reductions in soluble and peroxisomal catalase activities which could compromise mucosal protection against free radicals in dogs with aerobic overgrowth, and a loss of particulate malate dehydrogenase activity indicative of mitochondrial disruption in dogs with anaerobic overgrowth, were also reversed after treatment. These findings indicate that aerobic and anaerobic bacterial overgrowth can result in contrasting but potentially reversible damage to the jejunal mucosa which would not be detected by conventional investigative procedures.
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PMID:Response of the jejunal mucosa of dogs with aerobic and anaerobic bacterial overgrowth to antibiotic therapy. 337 16

In the epidermis of the fish Blennius sanguinolentus the histochemistry of complex carbohydrates and various oxidoreductases has been studied by means of a series of selected light microscopical techniques. The epidermis is endowed with three types of secretory cells namely, the mucous goblet cells, the superficial polygonal cells and the ionocytes, which provide protective functions in view of their involvement in the prevention of the skin epithelium from invading pathogens and in the osmoregulation processes respectively. The secretory substances of mucous goblet cells contain sulfated, carboxylated and neutral complex carbohydrates in addition to a glycoprotein with sialic acid terminal to galactose in its oligosaccharide chains. Activities of SDH, ICDH, MDH and G-6-PDH were studied, to elucidate some aspects of the correlated functions of the ionocytes which play a key role in the performance of the maintenance of the electrolyte pattern in the internal milieu of the skin. Differences in the intensity of various oxidoreductases are correlated with the extent of the activity of the epidermis for related to secretion of a mucous cover over the surface. Activity of the oxidoreductases is confined mainly to the basal and outer epidermal layers and this enzyme zonation is discussed with reference to the existence of the high turnover rate of the epithelial cells and both the proliferative and respiratory capabilities of the skin epithelium.
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PMID:Histochemical studies of acid proteoglycans and glycoproteins and activities of hydrolytic and oxidoreductive enzymes in the skin epidermis of the fish Blennius sanguinolentus pallas (Teleostei: Blenniidae). 640 48

Mouse A9 cells, L-cell-derived mutants deficient in hypoxanthine phosphoribosyltransferase (HPRT; IMP:pyrophosphate phosphoribosyltransferase, EC 2.4.2.8) were found to be incapable of binding (125)I-labeled epidermal growth factor (EGF) to the cell surface. The A9 cells were fused with human diploid fibroblasts (WI-38) possessing EGF-binding ability, and human-mouse cell hybrids (TA series) were isolated after hypoxanthine/aminopterin/thymidine/ouabain selection. Analyses of isozyme markers and chromosomes of four representative clones of TA hybrids indicated that the expression of EGF-binding ability is correlated with the presence of human chromosome 7 or 19. Four subclones were isolated from an EGF-binding-positive line, TA-4, and segregation of EGF-binding was found to be concordant with the expression of human mitochondrial malate dehydrogenase (MDHM; L-malate:NAD(+) oxidoreductase, EC 1.1.1.37), a marker for chromosome 7, but not with glucosephosphate isomerase (GPI; D-glucose-6-phosphate ketol-isomerase, EC 5.3.1.9), a marker for chromosome 19. Furthermore, evidence from 27 clones of AUG hybrids that were produced between A9 and another human fibroblast line, GM1696, carrying an X/7 chromosome translocation indicated that EGF-binding ability segregates together with human MDHM and two X-linked markers, HPRT and glucose-6-phosphate dehydrogenase (G6PD; D-glucose-6-phosphate:NADP(+) 1-oxidoreductase, EC 1.1.1.49), that are located on the translocation chromosome 7p(+). These results permit assignment of the gene, designated EGFS, which is associated with the expression of EGF-binding ability, to human chromosome 7 and its localization to the p22-qter region. Because the EGF receptor is reported to be a glycoprotein the EGFS could be either a structural gene(s) for receptor protein or a gene(s) for modifying the receptor protein through glycosylation.
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PMID:Genetics of cell surface receptors for bioactive polypeptides: binding of epidermal growth factor is associated with the presence of human chromosome 7 in human-mouse cell hybrids. 696 72

An N-acetylneuraminyl-alpha 2,3(6)lactose-malate dehydrogenase (MDH-Lac-Neu5Ac) conjugate is prepared via an isothiocyanate conjugation method using a p-aminophenethylamino derivative of sialyllactose. The newly synthesized conjugate can be utilized as a reagent in a novel homogeneous lectin-based, enzyme-linked, competitive binding assay (1-3) for probing the specific carbohydrate structure and content of intact glycoproteins. The enzymatic activity of the MDH-Lac-Neu5Ac conjugate is shown to be significantly inhibited (35%) by sialic acid-binding lectin, Limax flavus agglutinin (LFA), and this inhibition is reversed by mucin, a glycoprotein possessing sialic acid terminals. The asialo form of mucin, however, binds weakly to LFA, yielding no substantial increase in the MDH-Lac-Neu5Ac activity at comparable glycoprotein concentrations. Use of the newly synthesized conjugate in conjunction with LFA or other lectins capable of binding sialic acid may provide a rapid and convenient way to detect the presence and relative amount of sialic acid terminal groups within intact glycoprotein structures.
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PMID:Synthesis of N-acetylneuraminyl-alpha 2,3(6)lactose-malate dehydrogenase conjugate for detecting sialic acid terminal groups on glycoproteins via homogeneous lectin-based enzyme-linked binding assay. 937 29

Calnexin (CNX) and its soluble homologue calreticulin (CRT) are lectin-like molecular chaperones that help newly synthesized glycoproteins to fold correctly in the rough endoplasmic reticulum (ER). To investigate the mechanism of glycoprotein-quality control, we have synthesized structurally defined high-mannose-type oligosaccharides related to this system. This paper describes the synthesis of the non-natural undecasaccharide 2 and heptasaccharide 16, designed as potential inhibitors of the ER quality-control system. Each possesses the key tetrasaccharide element (Glc1Man3) critical for the CNX/CRT binding, while lacking the pentamannosyl branch required for glucosidase II recognition. These oligosaccharides were evaluated for their ability to bind CRT by isothermal titration calorimetry (ITC). As expected, each of them had a significant affinity towards CRT. In addition, these compounds were shown to be resistant to glucosidase II digestion. Their activities in blocking the chaperone function of CRT were next measured by using malate dehydrogenase (MDH) as a substrate. Their inhibitory effects were shown to correlate well with their CRT-binding affinities, both being critically dependent upon the presence of the terminal glucose (Glc) residue.
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PMID:Design and synthesis of oligosaccharides that interfere with glycoprotein quality-control systems. 1628 86

Monospecific antibodies raised against four glyoxysomal enzymes (isocitrate lyase, catalase, malate synthase, and malate dehydrogenase) have been used to detect these proteins among the products of in vitro translation in a wheat germ system programmed with cotyledonary RNA from cucumber seedlings. In vitro immunoprecipitates were compared electrophoretically with the same enzymes labeled in vivo and also with the purified proteins. Isocitrate lyase yields two bands on sodium dodecyl sulfate-polyacrylamide gels, as synthesized both in vitro (61.5K and 60K products) and in vivo (63K and 61.5K polypeptides). Both the 63K and 61.5K subunits can also be demonstrated for the isolated enzyme. The two subunits are antigenically cross-reactive and yield similar electrophoretic profiles upon partial proteolytic digestion. A larger subunit is seen in vitro than in vivo for both malate dehydrogenase (38K versus 33K) and catalase (55K versus 54K); this suggests a need for processing which is often a characteristic of proteins that must be transported across or into membranes. Malate synthase has a molecular weight of 57K both in vitro and in vivo, but the isolated enzyme is a glycoprotein, containing N-acetyl glucosamine, mannose, and possibly also fucose and xylose. This indicates that the polypeptide portion of the isolated enzyme is smaller than the in vitro product and suggests processing of malate synthase also. None of the other three enzymes appears to be glycosylated. The implications of these size differences for the compartmentalization of matrix and membrane-bound glyoxysomal enzymes are discussed.
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PMID:Regulation of Glyoxysomal Enzymes during Germination of Cucumber: 3. IN VITRO TRANSLATION AND CHARACTERIZATION OF FOUR GLYOXYSOMAL ENZYMES. 1666 Nov 39

Experiments were conducted to identify the differentially expressed proteins in rice (Oryza sativa L.) plants after treatment with the glycoprotein elicitor CSB I, purified from ZC(13), a race of the rice blast fungus Magnaporthe grisea. The interactions of two near isogenic lines of rice, C101A51 and CO39, with ZC(13) resulted in completely incompatible and compatible types, respectively. Proteins were extracted from rice leaves at 12 and 24 h after treatment with CSB I. Temporal changes in total proteins were examined using 2-DE. Among more than 900 protein spots reproducibly detected on each gel, 11 were up-regulated, three were down-regulated and seven were newly induced during, at a minimum, one time point. Twenty-one differentially expressed proteins were identified by linear ion trap quadrupole (LTQ)-MS/MS. The identified proteins were classified into six categories based on their putative function reported: (i) defense proteins (PR-10a, PR-5 and putative salt-induced protein), (ii) signal transduction (nucleoside diphosphate kinase and putative profilin), (iii) ROS (Mn-SOD, Cu/Zn-SOD, GST and CAT), (iv) programmed cell death (translationally controlled tumor protein), (v) molecule biosynthesis (putative ribosomal protein S5, putative ribosomal protein L12, putative translational elongation factor Tu and putative chaperonin 21 precursor) and (vi) metabolism (putative fructose-bisphosphate aldolase class-I, putative malate dehydrogenase, cytoplasmic malate dehydrogenase, putative acid phosphatase, putative transketolase1 and gamma hydroxybutyrate dehydrogenase-like protein). All of these proteins (except Cu/Zn-SOD, putative acid phosphatase and translationally controlled tumor protein) were induced faster and to a higher degree in C101A51 than in CO39. These data suggest that the incompatible rice line may possess a more sensitive recognition system that can identify and react to specific chemical, biological or physical triggers in a more efficient manner, thus eliciting an early and fast defense response.
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PMID:Identification of elicitor-responsive proteins in rice leaves by a proteomic approach. 1940 28

To gain more insights into the translational and PTM that occur in rat offspring exposed to alcohol in utero, 2-D PAGE with total, phospho- and glycoprotein staining and MALDI-MS/MS and database searching were conducted. The results, based on fold-change expression, revealed a down-regulation of total protein expression by prenatal alcohol exposure in 7-day-old and 3-month-old rats. There was an up-regulation of protein phosphorylation but a down-regulation of glycosylation by prenatal alcohol exposure in both age groups. Of 31 protein spots examined per group, differentially expressed proteins were identified as ferritin light chain, aldo-keto reductase, tumor rejection antigen gp96, fructose-1,6-bisphosphatase, glycerol-3-phosphate dehydrogenase, malate dehydrogenase, and gamma-actin. Increased phosphorylation was observed in proteins such as calmodulin, gluthatione S-transferase, glucose regulated protein 58, alpha-enolase, eukaryotic translation elongation factor 1 beta-2, riboprotein large P2, agmatinase, ornithine carbamoyltransferase, quinolinate phosphoribosyltransferase, formimidoyltransferase cyclodeaminase, and actin. In addition, glycosylation of adenosine kinase, adenosylhomocysteine hydrolase, and 3-hydroxyanthranilate dioxygenase was reduced. Pathways affected by these protein alterations include cell signaling, cellular stress, protein synthesis, cytoskeleton, as well as glucose, aminoacid, adenosine and energy metabolism. The activity of the gluconeogenic enzyme fructose-1,6-bisphosphatase was elevated by prenatal alcohol. The observations may have important physiological implications.
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PMID:Prenatal alcohol exposure alters phosphorylation and glycosylation of proteins in rat offspring liver. 1994 8


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