Lactate dehydrogenase isozymes from heart and white muscle of water-breathing and air-breathing fish from the Amazon

1978 ◽  
Vol 56 (4) ◽  
pp. 769-773 ◽  
Author(s):  
C. J. French ◽  
P. W. Hochachka

Lactate dehydrogenase (LDH, EC 1.1.1.27) isozymes were studied from the white muscle and hearts of four species of Amazon fish, Osteoglossum bicirrhosum, an obligate water breather, and the closely related air breather, Arapaima gigas; Hoplias malabaricus, an obligate water breather, and Hoplerythrinus unitaeniatus, a facultative air breather. The LDH pattern was similar in closely related species but could not be correlated with changes in respiratory habits. All the isozymes from both heart and white muscle showed low substrate inhibition by pyruvate. The LDH from Osteoglossum skeletal white muscle showed sigmoidal kinetics with respect to pyruvate, rendered hyperbolic by the addition of 20 mM phosphocreatine. The kinetic properties appear to facilitate a dual function for white muscle in the absence of red muscle in the myotome. Phosphocreatine inhibition of LDH was observed in all the tissues studied and is suggested to be a more general phenomenon than has been previously supposed.

1978 ◽  
Vol 56 (1) ◽  
pp. 128-135 ◽  
Author(s):  
W. C. Hulbert ◽  
T. W. Moon

The activities of lactate dehydrogenase (LDH) (L-lactate: NAD+ oxidoreductase, EC 1.1.1.27) can be divided into a lactate oxidase (lactate to pyruvate) and pyruvate reductase (pyruvate to lactate) component. These activities were examined in red and white muscle excised from the American eel Anguilla rostrata as an estimate of tissue lactate utilization, and compared with the kidney, gill, heart, and liver patterns. Phosphoenol pyruvate carboxykinase (PEP CK) activities in red and white muscle and liver were estimated as a marker for tissue gluconeogenic potential. Consistent with the possibility of lactate utilization for gluconeogenesis, both red muscle and liver possessed an active PEP CK and a bifunctional LDH, where oxidase activities were of the same magnitude as reductase activities. Kidney, which in mammals possesses gluconeogenic capabilities, together with heart and gill, also demonstrated LDH profiles consistent with the liver and red muscle enzymes. White muscle LDH was found to be essentially a pyruvate reductase and no PEP CK activity could be detected. These results suggest that eel red muscle has the potential to utilize lactate and has at least some of the enzymes required for gluconeogenesis. Therefore, the capacity of red muscle to perform a metabolic recycling function in addition to contraction cannot be excluded.


1990 ◽  
Vol 267 (1) ◽  
pp. 51-58 ◽  
Author(s):  
S H Chiou ◽  
H J Lee ◽  
G G Chang

Biochemical characterization and kinetic analysis of epsilon-crystallin from the lenses of common ducks were undertaken to elucidate the enzyme mechanism of this unique crystallin with lactate dehydrogenase (LDH) activity. Despite the structural similarities between epsilon-crystallin and chicken heart LDH, differences in charge and kinetic properties were revealed by isoenzyme electrophoresis and kinetic studies. Bi-substrate kinetic analysis examined by initial-velocity and product-inhibition studies suggested a compulsory ordered Bi Bi sequential mechanism with NADH as the leading substrate followed by pyruvate. The products were released in the order L-lactate and NAD+. The catalysed reaction is shown to have a higher rate in the formation of L-lactate and NAD+. Substrate inhibition was observed at high concentrations of pyruvate and L-lactate for the forward and reverse reactions respectively. The substrate inhibition was presumably due to the formation of epsilon-crystallin-NAD(+)-pyruvate or epsilon-crystallin-NADH-L-lactate abortive ternary complexes, as suggested by the product-inhibition studies. The significance and the interrelationship of duck epsilon-crystallin with other well-known LDHs are discussed with special regard to its role as a structural protein with some enzymic function in lens metabolism.


1993 ◽  
Vol 290 (1) ◽  
pp. 103-107 ◽  
Author(s):  
O Smékal ◽  
M Yasin ◽  
C A Fewson ◽  
G A Reid ◽  
S K Chapman

L-Lactate dehydrogenase (L-LDH) from Saccharomyces cerevisiae and L-mandelate dehydrogenase (L-MDH) from Rhodotorula graminis are both flavocytochromes b2. The kinetic properties of these enzymes have been compared using steady-state kinetic methods. The most striking difference between the two enzymes is found by comparing their substrate specificities. L-LDH and L-MDH have mutually exclusive primary substrates, i.e. the substrate for one enzyme is a potent competitive inhibitor for the other. Molecular-modelling studies on the known three-dimensional structure of S. cerevisiae L-LDH suggest that this enzyme is unable to catalyse the oxidation of L-mandelate because productive binding is impeded by steric interference, particularly between the side chain of Leu-230 and the phenyl ring of mandelate. Another major difference between L-LDH and L-MDH lies in the rate-determining step. For S. cerevisiae L-LDH, the major rate-determining step is proton abstraction at C-2 of lactate, as previously shown by the 2H kinetic-isotope effect. However, in R. graminis L-MDH the kinetic-isotope effect seen with DL-[2-2H]mandelate is only 1.1 +/- 0.1, clearly showing that proton abstraction at C-2 of mandelate is not rate-limiting. The fact that the rate-determining step is different indicates that the transition states in each of these enzymes must also be different.


1978 ◽  
Vol 56 (4) ◽  
pp. 736-750 ◽  
Author(s):  
P. W. Hochachka ◽  
M. Guppy ◽  
H. E. Guderley ◽  
K. B. Storey ◽  
W. C. Hulbert

To delineate what modifications in muscle metabolic biochemistry correlate with transition to air breathing in fishes, the myotomal muscles of aruana, an obligate water breather, and Arapaima, a related obligate air breather, were compared using electron microscopy and enzyme methods. White muscle in both species maintained a rather similar ultrastructure, characterized by large-diameter fibers, very few mitochondria, and few capillaries. However, aruana white muscle displayed nearly fivefold higher levels of pyruvate kinase, threefold higher levels of muscle-type lactate dehydrogenase, and a fourfold higher ratio of fructose diphosphatase –phosphofructokinase activity; at the same time, enzymes in aerobic metabolism occurred at about one-half the levels in Arapaima. Red muscle was never found in the myotomal mass of aruana, but in Arapaima, red muscle was present and seemed fueled by glycogen, lipid droplets never being observed. From these and other data, it was concluded that in myotomal muscle two processes correlate with the transition to air breathing in Amazon osteoglossids: firstly, an emphasis in oxidative metabolism, and secondly, a retention of red muscle. However, compared with more active water-breathing species, Arapaima sustains an overall dampening of enzyme activities in its myotomal muscle, which because of the large myotome mass explains why its overall metabolic rate is relatively low. By keeping the oxidative capacity of its myotomal muscle low, Arapaima automatically conserves O2 either for a longer time or for other more O2-requiring organs in the body, a perfectly understandable strategy for an air-breathing, diving fish, comparable with that observed in other diving vertebrates. A similar comparison was also made of two erythrinid fishes, one that skimmed the O2-rich surface layers of water and one that obtained three quarters of its O2 from water, one quarter from air. Ultrastructural and enzyme data led to the unexpected conclusion that the surface skimmer sustained a higher oxidative capacity in its myotomal muscles than did the facultative air breather.


1972 ◽  
Vol 57 (2) ◽  
pp. 551-567
Author(s):  
T. YAMAMOTO

1. Electrical and mechanical properties of the red muscle (M. levator pinnae pectoralis) and white muscle (M. levator pinnae lateralis abdominis) in the silver carp (Carassius auratus Linné) were investigated by using caffeine and thymol. 2. A complete tetanus could be produced in the red muscle. But in the white muscle no tetanus was produced and there was a gradual decrease in tension during continuous stimulation, even at a frequency of 1 c/s or less. 3. Caffeine (0.5-1 mM) and thymol (0.25-0.5 mM) potentiated the twitch tension in both muscles without an increase in the resting tension; they produced a contracture in both muscles when the concentration was increased further. 4. The falling phase of the active state of contraction was nearly the same in both muscles and was prolonged by caffeine (0.5 mmM) and by thymol (0.25 mM). 5. The resting membrane potential of the red muscle was scarcely affected by caffeine (0.5-5 mM), whereas in the white muscles a depolarization of 10 mV was observed with caffeine of more than 2 mM. The resting potential of both muscles was little changed by o.25 mm thymol. However, at a concentration of more than 0.5mM thymol depolarized the membrane in both muscles to the same extent. 6. In caffeine (2-3 mM) solution the mean specific membrane resistance was reduced from 8.8 kΩ cm2 to 6.0 kΩ cm2 in the red muscle, and from 5.0 kΩ cm2 to 2.7 kΩ cm2 in the white muscle. In thymol (0.5-1 mM) solution it was reduced from 11.2 kΩcm2 to 6.5 kΩ cm2 in the red muscle, and from 5.4kΩ cm2 to 3.1 kΩ) cm2 in the white muscle. The specific membrane capacitance, calculated from the time constant and the membrane resistance, remained more or less the same in both muscles after a treatment with these agents. 7. Electrical properties of the muscles and the effects of caffeine and thymol on mechanical responses suggest that there are no fundamental differences between red and white muscles except for the excitation-contraction coupling. A lack of summation of twitch, a successive decline of twitch, and inability to produce potassium contracture in the white muscle may be due to the fact that the Ca-releasing mechanism is easily inactivated by depolarization of the membrane.


1989 ◽  
Vol 257 (2) ◽  
pp. R278-R283 ◽  
Author(s):  
S. P. Brooks ◽  
K. B. Storey

The glycolytic enzymes glycogen phosphorylase, phosphofructokinase (PFK), and pyruvate kinase (PK) were assessed in liver, heart, red muscle, and white muscle of aerobic and 5-h anoxic turtles (Pseudemys scripta) for changes in total activity and kinetic parameters. Anoxia induced statistically significant changes in these glycolytic enzymes in each of the four organs assayed. Compared with normoxic controls, anoxic liver showed a 3.3-fold increase in glycogen phosphorylase activity, a 1.5-fold increase in the PFK I50 value for citrate (concentration that inhibits initial activity by 50%), a 1.5-fold increase in the PFK Michaelis constant (Km) value for fructose 6-phosphate (P), and an increased maximal activity of PK. Anoxic heart muscle showed a 2.6-fold decrease in glycogen phosphorylase activity and, for PFK, a 1.7-fold decrease in the Km value for ATP and a twofold increase in the I50 value for citrate. In anoxic white muscle, PFK showed a fivefold lower Km value for fructose-6-P and a threefold lower activator concentration producing half-maximal activation (A50) for potassium phosphate than the aerobic enzyme form. Changes in anoxic white muscle PK included a twofold increase in the Km value for ADP and a 1.7-fold decrease in the I50 value for alanine. In red muscle, anoxia affected only the Km value for ATP, which was 50% higher than the value for the aerobic enzyme form. Fructose 2,6-diphosphate (P2) levels also decreased in heart muscle and increased in red and white muscle during anoxia.(ABSTRACT TRUNCATED AT 250 WORDS)


2011 ◽  
Vol 300 (4) ◽  
pp. R835-R843 ◽  
Author(s):  
Donato A. Rivas ◽  
Sarah J. Lessard ◽  
Misato Saito ◽  
Anna M. Friedhuber ◽  
Lauren G. Koch ◽  
...  

Chronic metabolic diseases develop from the complex interaction of environmental and genetic factors, although the extent to which each contributes to these disorders is unknown. Here, we test the hypothesis that artificial selection for low intrinsic aerobic running capacity is associated with reduced skeletal muscle metabolism and impaired metabolic health. Rat models for low- (LCR) and high- (HCR) intrinsic running capacity were derived from genetically heterogeneous N:NIH stock for 20 generations. Artificial selection produced a 530% difference in running capacity between LCR/HCR, which was associated with significant functional differences in glucose and lipid handling by skeletal muscle, as assessed by hindlimb perfusion. LCR had reduced rates of skeletal muscle glucose uptake (∼30%; P = 0.04), glucose oxidation (∼50%; P = 0.04), and lipid oxidation (∼40%; P = 0.02). Artificial selection for low aerobic capacity was also linked with reduced molecular signaling, decreased muscle glycogen, and triglyceride storage, and a lower mitochondrial content in skeletal muscle, with the most profound changes to these parameters evident in white rather than red muscle. We show that a low intrinsic aerobic running capacity confers reduced insulin sensitivity in skeletal muscle and is associated with impaired markers of metabolic health compared with high intrinsic running capacity. Furthermore, selection for high running capacity, in the absence of exercise training, endows increased skeletal muscle insulin sensitivity and oxidative capacity in specifically white muscle rather than red muscle. These data provide evidence that differences in white muscle may have a role in the divergent aerobic capacity observed in this generation of LCR/HCR.


1993 ◽  
Vol 181 (1) ◽  
pp. 213-232 ◽  
Author(s):  
T. H. Yang ◽  
G. N. Somero

The effects of feeding and fasting were examined on the deep-living short-spine thornyhead (Sebastolobus alascanus) and the confamilial shallow-living spotted scorpionfish (Scorpaena guttata) to determine whether the low metabolic rate of the deeper-living species was in part a consequence of food deprivation in its habitat. Laboratory acclimation for periods of 90–115 days under either ad libitum feeding or complete fasting did not lead to similar rates of respiration in individuals of the two species held under identical conditions. Respiration of fish fed ad libitum was 52 % (S. guttata) or 68 % (S. alascanus) higher than for fasted fish of the same species. Furthermore, the metabolic rates of freshly collected specimens of S. alascanus resembled those of laboratory-fasted fish. In white skeletal muscle, both total protein concentration and the activities of four enzymes of ATP metabolism, lactate dehydrogenase (LDH) and pyruvate kinase (PK) of glycolysis, malate dehydrogenase (MDH) and citrate synthase (CS, a citric acid cycle indicator), were lower in S. alascanus than in S. guttata. Within a species, protein concentration and activities of the four enzymes in white muscle, but not in brain, were higher in fed than in starved fish, although these differences were greater in S. alascanus than in S. guttata. During fasting, LDH and PK activity in white muscle of S. alascanus decreased much more than MDH and CS activity; decreases in enzyme activities in red muscle were smaller than those in white muscle. Activities of enzymes in white skeletal muscle of field-collected S. alascanus generally resembled those of the fasted specimens. In contrast, red muscle of field- collected S. alascanus, compared with that of either fed or starved laboratory-held specimens, had a highly glycolytic poise (high LDH and PK activities relative to MDH and CS activities), which may suggest that muscle enzyme activities in the field-collected fish reflect adaptation to the low oxygen level in its adult habitat, the oxygen minimum layer. The strong correlations found between tissue biochemical properties and respiration rate allow us to develop a predictive index for metabolic rate from simple biochemical analyses, e.g. white muscle protein content or CS activity. We conclude that the low metabolic rate of S. alascanus is due to at least four depth-related factors: reduced abundance of food, low temperature, low ambient oxygen concentration and darkness, which may select for reduced locomotory activity.


1981 ◽  
Vol 59 (10) ◽  
pp. 1909-1915 ◽  
Author(s):  
V. Krishna Murthy ◽  
P. Reddanna ◽  
M. Bhaskar ◽  
S. Govindappa

Freshwater fish, Tilapia mossambica (Peters), were subjected to acute exposure and acclimation to sublethal acid water (pH 4.0), and the muscle metabolism was investigated. Differential patterns of carbohydrate metabolism were witnessed in the red and white muscles in response to both acute exposure and acclimation. The glycogen content of red muscle was elevated whereas that of white muscle was depleted on acute exposure. But on acclimation, both the muscles had elevated glycogen content. The red muscle seems to mobilize carbohydrates into both hexose mono- and di-phosphate pathways, but white muscle does so only into the hexose monophosphate pathway on acclimation. In general, both the muscles exhibited suppressed glycolysis and elevated oxidative phase leading to elevated glycogen level. The muscle metabolism was oriented towards conservation of carbohydrates and lesser production of organic acids on acclimation, as a possible metabolic adaptive mechanism of the fish, enabling them to counteract the imposed acid stress.


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