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)

NADP-linked malic enzyme (malate dehydrogenase (oxaloacetate-decarboxylating) NADP+, EC 1.1.1.40) has been partially purified from adult Onchocerca volvulus and Dirofilaria immitis. Suramin was found to inhibit the activity of malic enzyme from both filarial worms. The inhibition constants for suramin were calculated to be 0.011 microM and 0.015 microM for the enzymes from O. volvulus and D. immitis, respectively. In the case of NADP-linked malic enzyme from Trypanosoma brucei and chicken liver the inhibition by suramin was less pronounced. The inhibition constants were found to be 0.8 microM and 2.5 microM for the protozoan and vertebrate enzymes, respectively. The type of inhibition was competitive with respect to malate. The Michaelis constants for malate and pyruvate were determined to be 0.9 and 4.5 mM for O. volvulus and 0.85 and 5.0 mM for D. immitis, respectively. The low Km values for malate compared to those for pyruvate and the about 15-fold greater turnover in the direction of decarboxylation compared to carboxylation indicated that malic enzyme from both filarial sources might be involved in an alternative pathway leading from phosphoenolpyruvate via oxaleacetate, malate and pyruvate to lactate. It is suggested, that the inhibition of malic enzyme activity from O. volvulus by suramin might interfere with the generation of NADPH for biosynthetic reactions.
Mol Biochem Parasitol 1981 Nov
PMID:Inhibition of NADP-linked malic enzyme from Onchocerca volvulus and Dirofilaria immitis by suramin. 732 87

The hydrogen photoevolution was studied to compare the efficiency of chloroplasts or solubilized chlorophyll in the presence of hydrogenase from Clostridium butyricum and methylviologen which links the electron transfer from photosystems to the exogenous enzyme. The hydrogen evolution by chloroplasts in the absence of exogeneous electron donors (or in the presence of irreversibly oxidized dithiotreitol or cysteine) is probably limited by cyclic electron flow shot-circuiting the photosystem 1. Efficiency of hydrogen photoproduction when ascorbate or NADP.H are used as electron donors is probably limited by reverse reaction of photoreduced methylviologen with the oxidized electron donor. The combination of both dithiotreitol and ascorbate prevents the shot-circuiting of photosystem 1 by methylviologen; in this case the maximum efficiency of hydrogen photoevolution was achieved up to 400 mumol H2 per 1 mg chlorophyll per hour.
Mol Biol (Mosk)
PMID:[Conditions for effective hydrogen photoevolution by chloroplasts in the presence of bacterial hydrogenase]. 738 27

Expression of the Neurospora crassa am (NADP-specific glutamate dehydrogenase) gene is controlled by two upstream enhancer-like elements designated URSam alpha and URSam beta. URSam alpha is localized between - 1.3 and - 1.4 kb with respect to the major transcriptional start site. Deletion of a 90 bp sequence containing this element resulted in the loss of approximately 50% of normal glutamate dehydrogenase expression. Gel mobility shift analysis indicated that a nuclear protein from Neurospora binds in a specific manner to sequences within the 90 bp fragment. We have now used a combination of ion-exchange and affinity chromatography to purify this nuclear protein, which we call Am Alpha Binding protein (AAB). The activity was monitored by gel shift analysis. The protein was purified more than 14,000-fold with a yield of approximately 7%. The purified protein appears as a heteromer on denaturing polyacrylamide gel electrophoresis, with only two strong bands visible in silver-stained preparations. One band has an apparent molecular mass of 40 kDa, the other appears as a doublet with an apparent molecular mass of 30 kDa. DNAse I protection analysis indicated a protected region consisting of 30 bp, which contains a CCAAT pentanucleotide motif. Mutagenesis of the CCAAT motif abolished the binding of AAB to the DNA fragment.
Mol Gen Genet 1995 Nov 27
PMID:Purification of a heteromeric CCAAT binding protein from Neurospora crassa. 750 Sep 55

11 beta-Hydroxysteroid dehydrogenase (11 beta-HSD) is a microsomal enzyme complex responsible for the interconversion of active 11-hydroxy glucocorticoids to inactive 11-oxo metabolites. It has long been controversially discussed whether 11-dehydrogenation and 11-oxoreduction are catalysed by a single bidirectional enzyme or if the 11 beta-HSD system comprises 2 kinetically distinct microsomal enzyme activities, 11-dehydrogenase and 11-oxoreductase. However, 11-oxoreduction of homogeneously purified 11 beta-HSD could not be demonstrated under in vitro conditions until today. We have purified 11 beta-HSD from mouse liver microsomes to homogeneity by a purification method which affords a gentle membrane protein solubilization as well as providing a favourable detergent surrounding during the various chromatographic steps. Following 11-dehydrogenation of corticosterone and 11-oxoreduction of dehydrocorticosterone simultaneously throughout the entire purification procedure we could demonstrate that 11 beta-HSD retains both oxidative and reductive activities in almost the same ratio, which is also true for the homogeneously purified enzyme. Deducing from the coincidentally increasing specific activities of 11-dehydrogenation and 11-oxoreduction the conclusion can be drawn that both activities reside within the same protein. Furthermore, in addition to NADP(H) also NAD(H) can serve as cosubstrate, which is mainly true for the oxidative direction. In conclusion, our results provide evidence that the oxidative and reductive behaviour of 11 beta-HSD can be explained by the concept of a unique, reversible oxidoreductase thus disproving the two enzyme theory.
J Steroid Biochem Mol Biol 1994 Feb
PMID:The purification of 11 beta-hydroxysteroid dehydrogenase from mouse liver microsomes. 751 8

A human oxidoreductase (H-37) that is overexpressed in ethacrynic acid-resistant HT29 colon cells (Ciaccio, P. J., Stuart, J.E., and Tew, K.D. (1993) Mol. Pharmacol. 43, 845-853) has been identified as a dihydrodiol dehydrogenase. Translated protein from a dihydrodiol dehydrogenase cDNA isolated from a library prepared from ethacrynic acid-resistant HT29 cell poly(A+) RNA was recognized by anti-H-37 IgG and was identical in molecular weight with H-37. The isolated cDNA was identical in both nucleotide and amino acid sequences with the recently cloned liver dihydrodiol dehydrogenase (Stolz, A., Hammond, L., Lou, H., Takikawa, H., Ronk, M., and Shively, J.E. (1993) J. Biol. Chem. 268, 10448-10457). Using this cDNA as probe, we have examined its induction by Michael acceptors. The steady state dihydrodiol dehydrogenase mRNA level in the ethacrynic acid-resistant line was increased 30-fold relative to that of wild-type cells. Twenty-four hour treatment of wild-type cells with ethacrynic acid or dimethyl maleate increased mRNA 10-fold and 5-fold, respectively. These changes are accompanied by both increased protein expression and increased NADP-dependent 1-acenaphthenol oxidative activity in cell cytosol. In gel shift assays, compared to wild type controls, increased binding of NAD(P)H quinone oxidoreductase human antioxidant response element (hARE) DNA to redox labile protein complexes present in treated and resistant cell nuclear extract was observed. Ethacrynic acid induced CAT activity 2-fold in Hepa1 cells stably transfected with NAD(P)H quinone oxidoreductase hARE-tk-CAT chimeric gene construct. Thus, dihydrodiol dehydrogenase protein is inducible by de novo synthesis from mRNA by structurally related monofunctional inducer Michael acceptors. Altered in vitro binding of nuclear protein to the hARE is indirect evidence for the involvement of an element similar to hARE in the regulation of dihydrodiol dehydrogenase by these agents.
 ...
PMID:Regulation of human dihydrodiol dehydrogenase by Michael acceptor xenobiotics. 751 59

11 beta-Hydroxysteroid dehydrogenase (11 beta-HSD), responsible for the interconversion of hormonally active cortisol to inactive cortisone, dictates specificity for the mineralocorticoid receptor (MR) in the distal nephron and colon. Two isoforms of human 11 beta-HSD have been cloned, an NADP(H)-dependent (type 1) dehydrogenase/oxo-reductase enzyme, and a high-affinity NAD-dependent (type 2) unidirectional dehydrogenase. Using the reverse-transcriptase polymerase chain reaction (RT-PCR) amplification of RNA extracted from human adult tissues, type 1 11 beta-HSD mRNA was found in decidua, placenta, liver, lung, spleen, kidney medulla, cerebellum and pituitary, but was absent in kidney cortex, sigmoid and rectal colon, salivary gland and thyroid. In contrast, type 2 11 beta-HSD mRNA was found only in placenta and in the classical mineralocorticoid target tissues, kidney cortex, kidney medulla, sigmoid and rectal colon, salivary gland, and colonic epithelial cell lines (AAC1 and RGC28). In situ hybridization studies of renal cortex, cortico-medullary junction and medulla using a 35S-labeled antisense cRNA probe for type 2 human 11 beta-HSD, revealed specific localization of type 2 11 beta-HSD mRNA expression exclusively to renal cortical and medullary collecting ducts. Type 1 and type 2 isoforms of human 11 beta-HSD are expressed in a distinct tissue-specific fashion, in keeping with the proposed differences in their physiological roles. Type 2 11 beta-HSD is found predominantly in mineralocorticoid target tissues where it serves to protect the MR in an autocrine fashion.
Mol Cell Endocrinol 1995 Apr 28
PMID:Detection of human 11 beta-hydroxysteroid dehydrogenase isoforms using reverse-transcriptase-polymerase chain reaction and localization of the type 2 isoform to renal collecting ducts. 754 19

Non-phosphorylating glyceraldehyde 3-phosphate dehydrogenase (GAPDH, NADP-specific, EC 1.2.1.9) operates in the cytosol of autotrophic eukaryotes where it generates NADPH for biosynthetic processes from photosynthetic glyceraldehyde 3-phosphate exported from the chloroplast by the phosphate translocator. Here we report the first cloning and characterization of cDNAs encoding complete polypeptide chains of nonphosphorylating GAPDH from pea and maize by using oligonucleotide probes derived from amino acid sequences determined for the purified enzyme. Unexpectedly, nonphosphorylating GAPDH cannot be aligned with the well-known sequences of phosphorylating GAPDH, but shares about 30% amino acid identity with various specialized and non-specialized aldehyde dehydrogenases (ALDHs) of eubacteria and eukaryotes. A phylogenetic analysis of this ALDH superfamily reveals a complex evolutionary pattern with numerous major branches carrying genes from eubacteria, eukaryotes, or both, encoding enzymes that are specific or non-specific for particular aldehyde substrates. This topology suggests a concomitant emergence of multiple substrate specificities from non-specialized ALDH during an early evolutionary phase of intense metabolic diversification. Although unrelated at the sequence level, non-phosphorylating aldehyde dehydrogenases and phosphorylating GAPDH resemble one another with respect to catalytic hydride transfer and covalent thiol ester formation. Whether or not this reflects an ancestral relationship can only be decided when crystallographic data for ALDH enzymes have become available.
J Mol Biol 1994 Mar 18
PMID:Non-phosphorylating GAPDH of higher plants is a member of the aldehyde dehydrogenase superfamily with no sequence homology to phosphorylating GAPDH. 754 14

The secondary structure of human placental 17 beta-hydroxysteroid dehydrogenase in the absence and presence of NADP has been studied by circular dichroism spectroscopy. The conformational analysis of the NADP-containing enzyme shows that is an alpha/beta protein with 60% of regular secondary structure (38% of alpha helix, 22% of beta-strand structures), 20% of beta-turn and 20% of non-repetitive structure. These results were in good agreement with the information obtained using statistical and homology methods based on amino-acid sequence. On the other hand, 25% alpha-helix, 55% beta-strand, and 20% non-repetitive structure were estimated by circular dichroism for the cofactor-free enzyme. Addition of varying concentrations of NADP to the cofactor free enzyme is accompanied by circular dichroism spectral changes. From the variation in the magnitude of the positive band at 193 nm with increasing NADP concentration, a dissociation constant of 34 nM was obtained.
Biochem Mol Biol Int 1995 Jul
PMID:Human placental 17 beta-hydroxysteroid dehydrogenase: secondary structure and circular dichroism demonstration of conformational changes upon NADP binding. 754 54

In the adipose tissue, besides fatty acid synthesis (FA-S) from glucose, which includes several mitochondrial steps, FA-S from glutamate has been demonstrated. FA-S from glutamate takes place in the cytosol through the backward pathway of Krebs cycle (BPKC) and is due to the sequential action of (1) alanine aminotransferase (ALT, EC 2.6.1.2), which is presence of pyruvate converts glutamate to oxoglutarate; (2) isocitrate dehydrogenase (NADP) (ICDH, EC 1.1.1.42), which converts oxoglutarate to isocitrate; (3) aconitate hydratase (ACO, EC 4.2.1.3), which transforms isocitrate to citrate: and (4) ATP citrate-lyase (ATP-CL, EC 4.1.3.8), which splits citrate to yield the acetyl-CoA needed for FA-S. We studied the enzymes involved in BPKC in homogenates of human adipose tissue. In normal subjects, the cytosolic activity (mumol/min/g protein) was: ALT = 10.3 +/- 1.1, ICDH = 29.5 +/- 2.8, ACO = 2.05 +/- 0.23, and ATP-CL = 1.2 +/- 0.2. Mitochondria contained less or no activity, values being 20, 9, 11, and 0% of total for ATL, ICDH, ACO, and ATP-CL, respectively. BPKC enzymes are more active than the enzymes limiting FA-S from glucose, i.e., phosphofructokinase (EC 2.7.1.11), pyruvate carboxylase (EC 6.4.1.1), and pyruvate dehydrogenase (EC 1.2.4.1). In the obese patients, cytosolic ALT and ATP-CL were increased (12.9 +/- 0.7, P < 0.05, and 2.28 +/- 0.27, P < 0.01, respectively) compared to normal, while ICDH was not changed (ACO could not be studied). Similar changes were obtained by expressing enzyme activity per fat cell number.(ABSTRACT TRUNCATED AT 250 WORDS)
Biochem Mol Med 1995 Feb
PMID:Fatty acid synthesis from glutamate in the adipose tissue of normal subjects and obese patients: an enzyme study. 755 12

6-Phosphogluconate dehydrogenase (6PGDH) from rat-liver and kidney-cortex cytosol has been partially purified and almost completely isolated (more than 95%) from glucose-6-phosphate dehydrogenase activity. The purification and isolation procedures included high-speed centrifugation, 60-75% ammonium-sulphate fractionation, by which both hexose-monophosphate dehydrogenases activities were separated, and finally the protein fraction was applied to a chromatographic column of Sephadex G-25 equilibrated with 10 mM Tris-EDTA-NADP buffer, pH 7.6, to eliminate any contaminating metabolites. The kinetic properties of the isolated partially purified liver and renal 6PGDH were examined. The saturation curves of this enzyme in both rat tissues showed a typical Michaelis-Menten kinetic, with no evidence of co-operativity. The optimum pH for both liver and kidney-cortex 6PGDH was 8.0. The Km values of liver 6PGDH for 6-phosphogluconate (6PG) and for NADP were 157 microM and 258 microM respectively, while the specific activity measured at optimum conditions (pH 8.0 and 37 degrees C) was 424.2 mU/mg of protein. NADPH caused a competitive inhibition against NADP with an inhibition constant (Ki) of 21 microM. The Km values for 6PG and NADP from kidney-cortex 6PGDH were 49 microM and 56 microM respectively. The specific activity at pH 8.0 and 37 degrees C was 120.7 mU/mg of protein. NADPH also competitively inhibited 6PGDH activity, with a Ki of 41 microM. This paper describes a quick, easy and reliable method for the separation of the two dehydrogenases present in the oxidative segment of the pentose-phosphate pathway in animal tissues, eliminating interference in the measurements of their activities.
Mol Cell Biochem 1995 Mar 23
PMID:Kinetic properties of hexose-monophosphate dehydrogenases. II. Isolation and partial purification of 6-phosphogluconate dehydrogenase from rat liver and kidney cortex. 762 92


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