Further studies on the phylogenetic distribution of pyruvate oxidoreductase activities

• 1.1. The phylogenetic distribution of lactate, octopine, alanopine and strombine dehydrogenase activities (respectively, LDH, ODH, ADH and SDH) was examined in over 60 species from seven phyla and from three continents.
• 2.2. The results confirm and extend previously published data. Consistencies of distribution are observed at the levels of phyla, class, order and family.
• 3.3. Major observations include prominent SDH in the Porifera; LDH only in the Polyplacophera, Nudibranchia and Myidae (Mollusca) and nereid worms (Polychaeta); ODH and SDH in the marine pulmonate Melampus bidentatus (Basommatophora); high ADH to SDH ratios in marine gastropods; high ODH in active molluscs; and apparent SDH in the barnacle Lepas anatifera.
• 4.4. The results are discussed in relation to theories of opine pathway evolution and the newly discovered tauropine and β-alanopine opine dehydrogenases.

     

Distribution of beta-adrenergic binding in fractionated porcine adipocytes

• 1.1. The subcellular distribution of the porcine adipocyte beta-adrenergic receptor was studied in fractionated adipocytes.
• 2.2. The 30,000 g pellet obtained from hypotonically lysed cells contained membrane vesicles and mitochondria; it yielded approx 200–300 fmol dihydroalprenolol-bound receptors/mg protein.
• 3.3. Activity was increased to about 1000 fmol/mg protein after isolation of a plasma membrane fraction on a Percoll gradient.
• 4.4. The 5'-nucleotidase, succinate dehydrogenase and lactate dehydrogenase activities were usually enriched in compartments different from the ligand-binding activity.
• 5.5. Activity of porcine adipocyte 5'-nucleotidase, a purported plasma membrane marker enzyme, was not distributed in the same manner as the beta-adrenergic receptor.

     

Light-induced effects of several enzymes of carbohydrate metabolism in Phycomyces blakesleeanus

• 1.1. The photoregulation shown by glyceraldehyde 3-phosphate dehydrogenase and glucose 6-phosphate dehydrogenase appears to be independent of the mad gene product(s) and also independent of carotene biosynthesis regulation.
• 2.2. The photoregulation of malate dehydrogenase appeared to be dependent on the mutation of the mad and car S genes.
• 3.3. Pyruvate kinase and lactate dehydrogenase may be classified as light-independent.
• 4.4. The action of ATP and fructose 1,6-bisphosphate on the enzymes studied was generally independent of light/dark grown conditions.
• 5.5. However, the effect of fructose 1,6-bisphosphate on Phycomyces pyruvate kinase appears to be light-dependent.

     

Glycolytic enzymes of fowl and turkey spermatozoa

• 1.1. It was confirmed that, under anaerobic conditions, fowl spermatozoa formed lactate from glucose thirteen times faster than turkey spermatozoa.
• 2.2. The profiles of glycolytic enzyme activities were similar for spermatozoa from both species; however fowl spermatozoal activities were generally 2- to 4-fold higher.
• 3.3. Exceptions were glycerophosphate mutase and lactate dehydrogenase activities which were respectively 9.5 and 41 times greater in fowl spermatozoa.
• 4.4. In both species, spermatozoal glyceraldehyde-3-phosphate dehydrogenase had the lowest activity of the glycolytic enzymes.

     

A new glutamate dehydrogenase from Halobacterium halobium with different coenzyme specificity

• 1.1. Halobacterium halobium has two chromatographically distinct forms of glutamate dehydrogenase which differ in their thermolability and other properties. One glutamate dehydrogenase utilizes NAD, the other NADP as a coenzyme.
• 2.2. The NADP-specific glutamate dehydrogenase (EC 1.4.1.4) was purified 65-fold from crude extracts of H. halobium.
• 3.3. The Michaelis constants for 2-oxoglutarate (13.3 mM), ammonium (3.1 mM) and NADPH (0.077 mM) indicate that the enzyme catalyzes in vivo the formation of glutamate from ammonium and 2-oxoglutarate.
• 4.4. The amination of 2-oxoglutarate by NADP-specific glutamate dehydrogenase is optimal at the pH value of 8.0–8.5. The optimal NaCl or KCl concentration for the reaction is 1.6 M.
• 5.5. None of the several metabolites tested for a possible role in the regulation of glutamate dehydrogenase activity appeared to exert an appreciable influence on the enzyme.
• 6.6. NAD- and NADP-dependent glutamate dehydrogenases from H. halobium showed apparent molecular weights of 148,000 and 215,000 respectively.

     

Enzyme activities and level of SH groups in breast carcinomas

• 1.1. The carcinoma showed higher enzyme activities than the normal mammary tissue.
• 2.2. The ratios of glutamate dehydrogenase, glutathione reductase and catalase to lactate dehydrogenase were lower in carcinomas than in normal tissues. Similarly, the ratios of glutamate dehydrogenase, glutathione reductase and catalase to glucose-6-phosphate dehydrogenase were also significantly lower in carcinomas.
• 3.3. There were no significant differences in enzyme activities between stages I and II of disease, however in the metastatic tissues, there were significant differences between stages I and II.
• 4.4. SH groups were higher in the tissues of cancer patients than in normal tissues. The levels of thiols groups were higher in carcinomas at stage III of disease.

     

Kinetic behaviour of chicken liver mitochondrial malate dehydrogenase and lactate dehydrogenase mixtures

• 1.1. In the mitochondria of chicken liver cells there is lactate dehydrogenase activity that catalyses the reduction of the oxaloacetate by the NADH.
• 2.2. The presence of lactate dehydrogenase in the malate dehydrogenase preparations causes an apparent activation in the double-reciprocal plot at high oxaloacetate concentrations that depends on the lactate dehydrogenase/malate dehydrogenase ratio in the preparation.
• 3.3. The separation of the two molecular forms of chicken liver mitochondrial malate dehydrogenase, free from lactate dehydrogenase, is described.

     

Purification and some properties of isocitrate dehydrogenase of a blowfly Aldrichina grahami

• 1.1. NADH-dependent isocitrate dehydrogenase has been purified 110-fold from the crude extract of the flight muscle mitochondria of Aldrichina grahami.
• 2.2. The purification procedure involved Triton X-100 treatment of isolated mitochondria, column chromatography on DEAE-cellulose, Affi-gel blue, and P-cellulose.
• 3.3. The purified enzyme was homogeneous by criteria of the polyacrylamide gel electrophoresis.
• 4.4. The enzyme of the blowfly contains more acidic amino acids and less hydrophobic amino acids than that of pig heart.
• 5.5. The molecular weight was determined to be 330,000 daltons. The subunit construction differs from ghat of mammalian isocitrate dehydrogenase.

     

Purification and characterization of the d-lactate dehydrogenase from Leuconostoc lactis

• 1.1. The d-lactate dehydrogenase from Leuconostoc lactis has been purified in high yield.
• 2.2.The enzyme is a dimer of subunits of M_r = 39,000 and each subunit contains a single thiol group. The N-terminal residue is methionine.
• 3.3. The amino acid composition has been determined and is typical of that of a soluble globular protein.

     

NAD(P)H dehydrogenase from rabbit and rat liver: Purification and some properties

• 1.1. NAD(P)H dehydrogenase from rabbit liver was purified to electrophoretic homogeneity using a procedure also found applicable for the rat liver enzyme.
• 2.2. Rabbit and rat liver enzymes showed different behaviour in isoelectric focusing and different K_m values and turnover numbers.
• 3.3. Both enzymes were inhibited to similar extents by warfarin.
• 4.4. The rabbit enzyme is composed of two subunits of mol. wt 27,000 and contained 1 FAD group per subunit.
• 5.5. Some absorption and circular dichroism properties of the rat enzyme are shown.

     

Allozyme variation in the stingless bee Trigona fuscobalteata (hymenoptera,apidae) from Peninsular Malaysia

• 1.1. A population of Trigona fuscobalteata from Peninsular Malaysia was analysed for genetic variation at 9 gene-enzyme systems comprising 13 loci.
• 2.2. Two gene-enzyme systems (phosphoglucomutase and isocitrate dehydrogenase) were polymorphic in the 20 colonies studied.
• 3.3. Isocitrate dehydrogenase was represented by duplicate genes.
• 4.4. The number of loci for several enzyme systems appeared to be different from that reported for the Australian stingless bees.

     

The regulation of glucose 6-phosphate dehydrogenase from Dicentrarchus labrax (bass) liver

• 1.1. Kinetic constant values of the reaction catalyzed by bass liver glucose 6-phosphate dehydrogenase show to be modified between 10 and 40°C.
• 2.2. The Arrhenius plot between 10 and 50°C shows two slopes with different activation energies.
• 3.3. These results suggest a regulation of this enzyme by environmental temperature.
• 4.4. Kinetics of ATP inhibition were examined between pH 6.2 and 7.8: patterns and K_i values obtained are affected by the pH variation.
• 5.5. NADH is an effective inhibitor of bass glucose 6-phosphate dehydrogenase but this enzyme does not show NAD-linked activity.
• 6.6. Kinetics of pyridoxal 5′-phosphate inhibition have indicated the presence of a lysine in the catalytic site for NADP⁺.

     

Electrophoretic characterization of a hybrid between Eretmochelys imbricata and Caretta caretta (Cheloniidae)

• 1.1. An intermediate morphotype between Eretmochelys imbricata and Caretta caretta was studied in Praia do Forte, Bahia, Brazil.
• 2.2. Three enzymatic systems were successfully analyzed: SOD, lactate dehydrogenase (LDH) and esterase (EST). Isoelectric focusing of total soluble proteins of muscle and transferrin were shown.
• 3.3. Esterase exhibited nine phenotype patterns, seven in C. caretta and one in the others morphotypes. SOD phenotypes were identical in the three morphotypes. Lactate dehydrogenase and transferrins were characteristic for each species.
• 4.4. Jaccard's measure of similarity was calculated and a phenogram with the three morphotypes were constructed using isoelectric focusing of total soluble proteins.

     

Purification and characterization of hatching enzyme of the pike (Esox lucius)

• 1.1. A choriolytic enzyme was isolated from the hatching medium of the pike, Esox lucius.
• 2.2. The enzyme is defined as hatching enzyme.
• 3.3. The molecular weight of the enzyme is 24,000.
• 4.4. The enzyme is a glycoprotein containing 2% carbohydrate.
• 5.5. Its isoelectric point is 6.5.
• 6.6. The pH optimum is around pH 8.
• 7.7. The enzyme molecule contains two disulfide bonds but no free cysteine.
• 8.8. Inhibitor studies and metal analysis show that the enzyme is a zinc-metalloprotease.

     

The effect of γ-radiation on the NADP-MALIC enzyme from mango fruit,mangifera indica—I. Physico-chemical aspects

• 1.1. Malic enzyme purified from the fruit tissue of Mangifera indica was irradiated in dilute solution and the effect of γ-irradiation was investigated.
• 2.2. The activity of the enzyme decreased exponentially as a function of the applied dose under all conditions investigated. The inactivation yield (Go-value) in neutral solution and in air was 0.069.
• 3.3. The role of the radicals produced by water radiolysis in the inactivation of the enzyme was investigated by using different gas atmospheres and selective free radical-anions. The hydrogen atom and the hydrated electron (reducing species) were found to be important in the enzyme inactivation; as well as the possible destruction of cysteine and tryptophan residues.
• 4.4. The irradiated enzyme appears to adopt a more compact conformation as reflected in a slightly lower M_r, Stokes-radius and diffusion coefficient.
• 5.5. γ-Radiation does not lead to any heterogeneity in the charge and size properties of the enzyme and the pI and the M_r of the subunits were unaffected.
• 6.6. Some differences in the amino acid composition of the non-irradiated and irradiated enzyme were observed but specific amino acid residues were not preferentially destroyed.
• 7.7. These changes were also reflected in the ultraviolet spectrum of the enzyme which shifted to lower values.
• 8.8. The major cause of inactivation seem to be a change in conformation caused by chemical modification of amino acid side chains.

     

NADPH/NADP ratio could regulate the glyoxylate cycle in Tetrahymena pyriformis

• 1.1. The glyoxylic acid cycle pathway could be regulated through the modulation of the isocitrate dehydrogenase-NADP activity. This enzyme is inhibited by NADPH.
• 2.2. The effect on the glyoxylate cycle flux of variations in the rate of the NADPH-consuming pathways has been studied.
• 3.3. Increase in the rate of NADPH-consuming activity by addition of H₂O₂ produces inhibition of the glyoxylate cycle and decrease in the NADPH/NADP ratio.
• 4.4. These results suggest that the glyoxylate flux in Tetrahymena could be modulated by regulation of NADP-dependent isocitrate dehydrogenase by the NADPH/NADP ratio.

     

Proteolytic system in Babesia hylomysci

• 1.1. Babesia hylomysci has an aminopeptidase and an acid endoprotease
• 2.2. The amino-peptidase has properties very similar to the aminopeptidase in Plasmodium yoelii nigeriensis and P. chabaudi.
• 3.3. The acid endoprotease is specific towards haemoglobin and practically has no action on bovine serum albumin.
• 4.4. In mouse normal red blood cells we find an acid protease having physico-chemical properties similar to the enzyme present in B. hylomysci extracts.
• 5.5. The similarity of electrophoretic velocity between acid protease in B. hylomysci and non-infected red blood cells leads us to think that the acid protease of parasitic extracts comes from the host-cell.
• 6.6. The proteolytic system of Babesia and Plasmodium are similar.

     

Measurements of oxygen consumption in Mytilus edulis during exposure to,and recovery from,high sublethal concentrations of formaldehyde,benzene and phenol

• 1.1. The rate of oxygen consumption has been monitored continuously in M. edulis during acute exposure to high sublethal concentrations of formaldehyde, phenol and benzene and subsequent recovery periods of 96 hr.
• 2.2. The results are discussed in relation to changes in the electrochemical potential difference of sodium, the content of ATP and the tissue concentration of strombine.
• 3.3. After exposure to benzene and phenol, an increase in the rate of oxygen consumption that could not be explained by oxygen debt from the exposure period was observed.
• 4.4. Depression of the rate of oxygen consumption after exposure to formaldehyde may be explained by a reduced ability to extract oxygen from the water.
• 5.5. The pattern of oxygen consumption and behavioural responses, as well as the combined changes in the biochemical markers, were distinctly different in the three cases.

     

Effect of diet and essential amino acids gavage on young rat amino acid metabolism enzymes

• 1.1. The effects of a high-fat, high-energy diet and essential plus semi-essential amino acid gavage on pup rats have been studied (60–65 animals).
• 2.2. The activities of alanine transaminase, adenylate deaminase, glutamine synthetase and serine dehydratase have been tested in liver and muscle.
• 3.3. Plasma was used for the estimation of proteins, urea, amino acids, glucose, lactate, 3-hydroxy-butyrate and acetoacetate.
• 4.4. Liver and muscle glutamine synthetase activities are increased by diet and gavage administered. Hepatic serine dehydratase is inhibited by a cafeteria diet but activated by amino acid gavage. Adenylate deaminase is inhibited by diet and gavage in the liver, but gavage does not affect this enzyme activity in muscle. Liver alanine transaminase is increased by the diet; in the muscle, cafeteria diet and amino acid gavage showed the highest values for this enzyme.
• 5.5. In the plasma, the increase in lactate produced by the diet is inhibited by the amino acids provided. Cafeteria-fed pups showed lower urea levels and higher 3-hydroxybutyrate concentrations in the plasma.
• 6.6. Intracellular glucose is diminished by cafeteria diet. In contrast, the blood cell amino acid concentration increases with diet and gavage supplied.

     

Distribution of opine dehydrogenases and lactate dehydrogenase activities in marine animals

• 1.1. Opine dehydrogenases (OpDHs) and lactate dehydrogenase (LDH) activities were determined in various marine animals. OpDHs were detected in six marine invertebrate phyla; Porifera, Coelenterata, Annelida, Mollusca, Arthropoda and Echinodermata in phylogenic sequence.
• 2.2. Among several OpDHs, tauropine dehydrogenase (TaDH) occurred widely in marine invertebrates, from Porifera to Echinodermata.
• 3.3. With a few exceptions, total OpDHs activities exceeded that of LDH activity in the marine invertebrates investigated.
• 4.4. With respect to anaerobic glycolysis, OpDHs are indicated to play an important role in phylogenically lower invertebrates, whereas LDH is more important in higher animals.