The influence of ehrlich ascites tumour growth on the turnover of lactate dehydrogenase in tissues of the mouse

• 1.1. The influence of Ehrlich ascites tumour growth on the turnover of total soluble protein and lactate dehydrogenase (LDH) in mouse tissues has been studied.
• 2.2. Turnover parameters were determined by means of double-labelling technique, with the enzyme (LDH) being isolated by affinity chromatography.
• 3.3. Tumour growth was accompanied by a decreased rate of synthesis of total protein in all tissues.
• 4.4. Lactate dehydrogenase by contrast snowed an increased rate of synthesis in all tissues but kidney.
• 5.5. These directions of change, in combination with the lesser response of degradation constants, resulted in a consequent conservation of enzyme activity in all tissues except kidney.
• 6.6. A generalized shift in the LDH isozyme pattern of these tissues was also observed during tumour growth with an increased contribution of A-type subunit.
• 7.7. These results have been discussed in relation to the redirection of protein synthesis and degradation, the occurrence of foetal isozymes, and possible mechanisms involved in the redistribution of protein resources in the animal during tumour development.

     

Direct adaptation of cells to temperature: Similar changes of LDH isozyme patterns by in vitro and in situ adaptations in Xenopus laevis

• 1.1. Cells of Xenopus laevis were cultured in vitro chronically at different temperatures and their isozyme patterns of lactate dehydrogenase (LDH) were compared with those of liver of temperature-acclimated toads.
• 2.2. Relative increase of cathodic isozyme by cold adaptation was observed both in two independent cell lines and in toad tissue.
• 3.3. This supports the concept that adaptation of cells to local body temperature would be responsible to the change in isozyme pattern by temperature adaptation of organisms.
• 4.4. Such changes would not be a direct result of elevated pO₂, judging from tissue distribution of isozymes.

     

Evolution of LDH isozymes during programmed cell death

• 1.1. Lactic dehydrogenase dehydrogenase isozymes and other respiratory enzymes were studied in degenerating intersegmental muscles of Manduca sexta and Antheraea polyphemus.
• 2.2. Total activities of the different enzymes (isocitric dehydrogenase, malic dehydrogenase, catalase, lactic dehydrogenase) decline at varying rates, starting before the rapid phase of involution.
• 3.3. One isozyme of LDH, an M-type isozyme, increases several-fold during the final three days prior to the emergence of the insect.
• 4.4. The same isozyme appears very transiently or not at all in muscles which do not break down, and is present in degenerating silk glands at the time of their most rapid involution.
• 5.5. The data suggest that limitation of oxidative metabolism plays a role in the involution of the muscles.

     

Phylogeny and ontogeny of the phosphoglycerate mutases—I. Electrophoretic phenotypes of the glycerate-2,3-P2 dependent phosphoglycerate mutase in vertebrates

• 1.1. The electrophoretic phenotype of phosphoglycerate mutase in tissues from different classes of vertebrates at several stages of development have been analyzed on cellulose acetate.
• 2.2. Mammals, reptiles, amphibians and fish show a common three-banded isozyme pattern.
• 3.3. The three isozymes vary in their relative distribution from tissue to tissue and during growth.
• 4.4. In birds electrophoretically distinguishable phosphoglycerate mutase isozymes have not been detected.
• 5.5. The results support a genetic basis for the phosphoglycerate mutase isozymes and suggest that gene duplication may have occurred early in vertebrate evolution.

     

Lactate dehydrogenase isozymes of the leopard danio,Brachydanio nigrofasciatus: their characterization and ontogeny

• 1.1. The tissue specific patterns and ontogeny of lactate dehydrogenase (LDH) are reported.
• 2.2. While all tissues (eye, brain, heart, intestine, liver, ovary and skeletal muscle) show isozymes of A and B subunit composition, only liver extracts possess isozymes resulting from C subunit synthesis.
• 3.3. The A₄ homopolymer appears simultaneously with initial muscle contractility and is correlated with the physiological function of muscular contraction.
• 4.4. The activation of the Ldh-C locus is correlated with the first functioning of liver. It is suggested that the state of differentiation of liver cells may be the stimulus required for C locus expression.

     

The effect of thiamine deficiency on the turnover of lactate dehydrogenase in mouse tissues

• 1.1. Groups of mice were subjected to different degrees of thiamine deprivation in their diet. In particular, the effects of complete thiamine deficiency and a continuation of minimal nutritional levels of thiamine were compared.
• 2.2. The effects of these treatments on the turnover characteristics of lactate dehydrogenase and total soluble protein have been studied by means of double labelling experiments, and determinations of the relative emphases of synthesis and degradation of these tissue components.
• 3.3. Marked divergences from normal were apparent with each of these nutritional regimens-complete thiamine deficiency causing a considerably increased rate of degradation for both total protein and lactate dehydrogenase in all tissues; whereas maintenance of minimal levels of thiamine led to increased degradation of total protein in liver, but reduced rates of degradation for lactate dehydrogenase in brain, heart and liver.
• 4.4. The significance of these results has been discussed in relation to the relative influence of vitamin and calorie deficiencies on turnover parameters, the individuality of specific tissue behaviour, differences in protein redistribution in response to separate physiological perturbations, and the role of thiamine in specific proteolysis.

     

Purification and properties of allelic lactate dehydrogenase isozymes at the B2 locus in rainbow trout,Salmo gairdneri

• 1.1. The homotetrameric lactate dehydrogenase (LDH) isozymes, B₄^2′ and B₄^2″, from homozygous rainbow trout livers have been purified to homogeneity by affinity chromatography using a Sepharose-linked oxamate ligand.
• 2.2. The B₄^2″ isozyme has been found: (a) to have increased K_m (pyr) and K_i (lac) values, (b) to bind pyruvate strongly in the absence of coenzymes with a binding constant of 4.02 × 10⁴ M⁻¹ under conditions where other LDH isozymes showed no binding, and (c) to give a nonlinear noncompetitive lactate product inhibition pattern compared to a normal linear noncompetitive inhibition for the B₄^2′ isozyme.
• 3.3. Different kinetic mechanisms have been proposed for the two isozymes and an adaptive functional significance has been discussed.

     

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.

     

The turnover characteristics of carbonic anhydrase in mouse tissues

• 1.1. An affinity chromatography technique for the determination of turnover parameters has been applied to the study of carbonic anhydrase in a variety of mouse tissues.
• 2.2. The methodology has allowed the establishment of the relative turnover characteristics in these tissues, and the evaluation of the half lives and degradation rate constants.
• 3.3. Considerable variation was evident between the individual tissues, with synthesis being indicated as most rapid in intestine while degradation was highest in liver.
• 4.4. These data have been discussed in relation to available comparisons in the literature, and the known physiological correlations of carbonic anhydrase in these tissues.

     

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.

     

Multiple leucine aminopeptidases in the oocysts of Eimeria tenella and their changes during sporulation

• 1.1. There was little neutral protease activity but high levels of leucine aminopeptidases (LAP) in the oocysts of Eimeria tenella.
• 2.2. By electrophoretic analysis, there were three apparent LAP isozymes I, II and III in unsporulated oocysts.
• 3.3. They all diminished with the simultaneous emergence of a new, fast-moving isozyme V during late phase of sporulation.
• 4.4. The enzyme V was unlikely to have resulted from de novo protein synthesis and was predominantly in the cytoplasm surrounding the sporocysts.
• 5.5. It differed from the other isozymes by a slightly higher pH optimum, more dependence on Mn²⁺ or Mg²⁺ in the assay and higher susceptibility to chelating agents.
• 6.6. The possible biological function of these isozymes remain unknown. Since they were not found in sporozoites or merozoites of E. tenella, they may be needed only for sporulation and, possibly, excystation.

     

LDH isozymes in amazon fish—III. Distribution patterns and functional properties in Serrasalmidae (Teleostei: Ostariophysi)

• 1.1. The patterns of distribution of LDH isozymes in five tissues from 12 Serrasalmidae species have been studied through two-fold serial dilution (Klebe's test) as well as the pyruvate inhibition of LDH enzyme in skeletal and heart muscles (low/high ratios).
• 2.2. The species' electrophoretic patterns differ by orthologous A₄ isozyme mobilities since the orthologous B₄ isozymes present similar electrophoretic migration. These differences between Ldh-A and Ldh-B products reflect three-, four-, and five-banded patterns. Thus, different LDH isozyme numbers formed from A and B subunits should not be used as an evolutionary or phylogenetic characteristic from different taxonomic groups.
• 3.3. Out of 66 pairs of species only five pairs showed significant differences in the distribution patterns in all five analyzed tissues, while no pair of species showed the same distribution in these tissues. This variation was explained as differential regulation of structural genes among tissues and/or species.
• 4.4. Functional properties showed significant between the LDHs from heart and skeletal muscles, and are consistent with a preference for aerobic metabolism. We suppose that by selecting B-like subunits these fishes are able to maintain good control of aerobic/anaerobic transitions, maintaining predominantly oxidative metabolism even in hypoxic waters, with which they have to cope.

     

The stereospecific distribution and evolutionary significance of invertebrate lactate dehydrogenases

• 1.1. Diphosphopyridine nucleotide coenzyme-linked lactate dehydrogenases from 48 species representing six invertebrate phyla have been examined for lactate stereospecificity and starch gel electrophoretic mobility.
• 2.2. Every organism was found to contain enzyme activity for only one lactate stereoisomer, although in several cases multiple molecular forms were observed.
• 3.3. The minimum number of changes in stereospecificity to accommodate the evolution of the major invertebrate classes are four.
• 4.4. An alternative evolutionary tree for the invertebrates based on lactate dehydrogenase is presented which requires only one change in stereospecificity.

     

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.

     

Shift in vivo in the lactate dehydrogenase isoenzyme pattern in experimental models conditioning the metabolic adaptation of rat brain

• 1.1. In order to analyse the possible shift in the lactate dehydrogenase isoenzyme pattern, experimental models affecting the glycolytic pathway are developed, including phenylalanine, thiamine and epinephrine administration, and a vitamin free diet.
• 2.2. The results obtained show that a shift in the lactate dehydrogenase isoenzyme pattern occurs in every change in physiological condition.
• 3.3. These shifts are in accordance with the kinetic properties of each isoenzyme and account for a metabolic adaptation to each physiological state.

     

Comparison of activities of several enzymes and protein constituents of oviducal and breast muscle of Japanese quail,Coturnix coturnix Japonica

• 1.1. Activities of several enzymes and protein constituents of magnum, isthmus, shell gland and breast muscle (pectoralis major) of Japanese quail, Coturnix coturnix japonica were compared.
• 2.2. The respective activity per g wet weight of lactate dehydrogenase, malate dehydrogenase and l-glycerol 3-phosphate dehydrogenase in pectoralis major was approx 20 times that of these enzymes in isthmus which showed the highest activity among oviducal tissues. On the other hand, the respective activity of lactate dehydrogenase was similar to that of malate dehydrogenase and was approx 10–20 times that of l-glycerol 3-phosphate dehydrogenase in each tissue.
• 3.3. Among NADPH-producing enzymes, NADP⁺-isocitrate dehydrogenase showed the highest activity in all tissues. The activity of malic enzyme was lowest in oviducal tissues, but was next to NADP⁺-isocitrate dehydrogenase in pectoralis major.
• 4.4. Sodium dodecyl sulfate polyacrylamide gel electrophoretic patterns of the whole homogenate, the supernatant and the precipitate fraction of magnum, isthmus, shell gland and pectoralis major showed tissue specific protein compositions. Proteins with molecular weight of 55,000, 70,000, 110,000 and 130,000 were observed in the respective precipitate (myofibrilar) fraction of magnum, isthmus and shell gland, but not in that of pectoralis major. It was noteworthy that the amount of myosin heavy chain of magnum was markedly less than that of other three tissues.

     

Sex and tissue specific patterns of protein synthesis and turnover in the free-living nematode Panagrellus redivivus

• 1.1. A pulse-chase autoradiographic study of incorporation of ³H-leucine into body-wall, digestive and reproductive tissue of virgin adult Panagrellus redivivus demonstrates both tissue and sex-specific patterns of protein biosynthesis and turnover.
• 2.2. Female body wall has a higher rate of protein synthesis and turnover than male body wall.
• 3.3. Uptake of leucine into macromolecule in the digestive tissue is more rapid in males than females, as is the rate of turnover.
• 4.4. The ovary is more rapidly labelled than the testis, with a much more rapid turnover rate.

     

Novel amino acid linked dehydrogenase in the sponge Halichondria panicea (pallas)

• 1.1. The sponge Halichondria panicea has a complete sequence of glycolytic and tricarboxylic acid cycle enzymes.
• 2.2. However, there is no detectable lactate dehydrogenase in H. panicea and lactate dehydrogenase appears to be functionally replaced by an enzyme which catalyses the reductive condensation of pyruvate and glycine to yield 2-methylimino-diacetic acid (strombine).
• 3.3. The intracellular distribution and kinetic properties of this novel enzyme (strombine dehydrogenase) have been investigated and its role in metabolism is discussed.

     

Effects of niacin deficiency on the relative turnover rates of proteins in various tissues of Japanese quail

• 1.1. The effects of niacin deficiency on the relative turnover rates of proteins in various tissues of Japanese quail were investigated.
• 2.2. The level of liver NAD was not affected by niacin deficiency whereas the level of pectoral muscle NAD was markedly reduced.
• 3.3. In all dietary treatments the liver had the highest turnover rates of proteins, heart and brain had intermediate rates, and pectoral muscle had the lowest rates.
• 4.4. Relative turnover rates of proteins in all tissues (particularly pectoral muscle) of the niacin deficient group were significantly higher than those of pair-fed control group, although there were no significant differences in turnover rate between pair-fed control and control groups.
• 5.5. The high turnover rate of proteins in niacin deficiency was primarily attributed to enhanced degradation rate of proteins rather than enhanced synthesis rate of proteins.
• 6.6. Optical density scanning (or densitometric) of water-soluble pectoral muscle proteins separated by isoelectric focusing revealed several additional minor protein bands between major protein bands in the niacin deficient group which were more pronounced in the acidic region of the gel.
• 7.7. These results suggest that proteins with a low pI value in pectoral muscle of the niacin deficient animal are highly sensitive to protein degradation.

     

1H NMR study of metabolic alterations in the small intestine of rats infected with Hymenolepis diminuta

• 1.1. 1H NMR spectra of the duodenum, jejunum and ileum tissues of the small intestine of a rat showed metabolic gradients.
• 2.2. The concentrations of metabolites in these gut regions were altered by the presence of the tapeworm Hymenolepis diminuta.
• 3.3. In the infected duodenum there was significantly less glycogen, glucose and phosphocreatine/creatine, but significantly more lactate than in the corresponding controls.
• 4.4. Infected jejunum contained significantly less betaine but significantly more succinate, alanine and lactate.
• 5.5. Infected ileum had significantly less glycogen and taurine but significantly more alanine and lactate.