Transient time of the pyruvate kinase-lactate dehydrogenase system of rabbit muscle in vitro

FEBS Letters ◽  
1970 ◽  
Vol 9 (2) ◽  
pp. 73-77 ◽  
Author(s):  
B. Hess ◽  
B. Wurster
Keyword(s):  
Lactate Dehydrogenase ◽  
Pyruvate Kinase ◽  
Rabbit Muscle ◽  
Transient Time ◽  
Dehydrogenase System

scholarly journals Re-evaluation of the glycerol-3-phosphate dehydrogenase/l-lactate dehydrogenase enzyme system. Evidence against the direct transfer of NADH between active sites

1991 ◽  
Vol 278 (3) ◽  
pp. 875-881 ◽  
Author(s):  
S P J Brooks ◽  
K B Storey
Keyword(s):  
Lactate Dehydrogenase ◽  
Active Sites ◽  
Reaction Rate ◽  
Experimental Results ◽  
Transfer Model ◽  
Rabbit Muscle ◽  
Direct Transfer ◽  
Theoretical Predictions ◽  
Glycerol 3 Phosphate Dehydrogenase

An investigation of the direct transfer of metabolites from rabbit muscle L-lactate dehydrogenase (LDH, EC 1.1.1.27) to glycerol-3-phosphate dehydrogenase (GPDH, EC 1.1.1.8) revealed discrepancies between theoretical predictions and experimental results. Measurements of the GPDH reaction rate at a fixed NADH concentration and in the presence of increasing LDH concentrations gave experimental results similar to those previously obtained by Srivastava, Smolen, Betts, Fukushima, Spivey & Bernhard [(1989) Proc. Natl. Acad. Sci. U.S.A. 86, 6464-6468]. However, a mathematical solution of the direct-transfer-mechanism equations as described by Srivastava et al. (1989) showed that the direct-transfer model did not adequately describe the experimental behaviour of the reaction rate at increasing LDH concentrations. In addition, experiments designed to measure the formation of an LDH4.NADH.GPDH2 complex, predicted by the direct-transfer model, indicated that no significant formation of tertiary complex occurred. An examination of other kinetic models, developed to describe the LDH/GPDH/NADH system better, revealed that the experimental results may be best explained by assuming that free NADH, and not E1.NADH, is the sole substrate for GPDH. These results suggest that direct transfer of NADH between rabbit muscle LDH and GPDH does not occur in vitro.

Inactivation in Vitro of Lactate Dehydrogenase-5 in Blood

1977 ◽  
Vol 14 (1-6) ◽  
pp. 48-52 ◽  
Author(s):  
A. R. Qureshi ◽  
J. H. Wilkinson
Keyword(s):  
Enzyme Activity ◽  
Lactate Dehydrogenase ◽  
Whole Blood ◽  
Rabbit Muscle ◽  
Muscle Lactate ◽  
Rabbit Blood

During incubation with rabbit blood in vitro rabbit-muscle lactate dehydrogenase-5 was inactivated at a rate similar to that observed in vivo. By contrast plasma and plasma containing erythrocytes had no effect on the enzyme activity, but plasma containing leucocytes inactivated the enzyme at the same rate as whole blood. The results obtained support the concept that intravascular inactivation accounts for the disappearance of enzymes from the circulation.

In vitro Thermal and Salt Stability of Pyruvate Kinase Are Increased by Proline Analogues and Trigonelline

1991 ◽  
Vol 18 (3) ◽  
pp. 279 ◽  
Author(s):  
a Shomer-Ilan ◽  
GP Jones ◽  
LG Paleg
Keyword(s):  
Zea Mays ◽  
Enzyme Activity ◽  
Pyruvate Kinase ◽  
Compatible Solutes ◽  
Rabbit Muscle ◽  
Protective Effects ◽  
Protective Properties ◽  
Nitrogenous Compounds

The nitrogenous compounds N-methyl-L-proline (MP), trans-4-hydroxy-N-methyl-L-proline (MHP) and trigonelline (T), which undergo stress-induced accumulation in some Australian plants, were analysed and compared with proline (P) and glycinebetaine (B) for possible protective roles. The activity of pyruvate kinase (PK), prepared from Zea mays leaves and rabbit muscle, was unaffected even in the presence of 750 mM of the proline analogues. Thus, MP and MHP, like P and B, have the properties to act in vivo as compatible osmotica. T was not as compatible, decreasing enzyme activity 20% at 0.5 M. Like P and B, however, MP, MHP and T all also exhibited protective properties. They increased, in vitro, the thermal stability of PK from both plant and animal sources, and they protected PK (Zea mays) from salt inhibition at two substrate levels. The effect of salt on PK (Zea mays) was substrate dependent; at low phosphoenolpyruvate (PEP) levels, salt inhibited the enzyme activity, while salt effects were less severe in the presence of higher substrate levels. In the presence of high NaCl concentrations, the protective effects of high substrate levels and the compatible solutes seem to be additive. The Km (PEP) value of the plant PK increased in the presence of salt but the effect was ameliorated by the compatible solute MHP.

scholarly journals Phosphocreatine does not inhibit rabbit muscle phosphofructokinase or pyruvate kinase.

1979 ◽  
Vol 254 (22) ◽  
pp. 11357-11359
Author(s):  
C.D. Fitch ◽  
R. Chevli ◽  
M. Jellinek
Keyword(s):  
Pyruvate Kinase ◽  
Rabbit Muscle
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