Yeast pyruvate kinase. Native and subunit molecular weight

Biochemistry ◽  
1970 ◽  
Vol 9 (10) ◽  
pp. 2043-2047 ◽  
Author(s):  
R. T. Kuczenski ◽  
C. H. Suelter
1988 ◽  
Vol 34 (10) ◽  
pp. 1154-1158 ◽  
Author(s):  
Harry C. M. Kester ◽  
Jos H. A. A. Uitzetter ◽  
Leo H. de Graaff ◽  
Jaap Visser

Pyruvate kinase was purified from the filamentous fungus Aspergillus nidulans with a 45–55% yield. The procedure involved dye-affinity chromatography and fast protein liquid chromatography, resulting in highly active and pure enzyme in milligram quantities within 2 days. The purified enzyme, a tetramer with a subunit molecular weight of 65 000 and an isoelectric point of 4.7, was used to determine the amino acid composition.


1974 ◽  
Vol 52 (10) ◽  
pp. 894-902 ◽  
Author(s):  
Hans W. Behrisch

Liver of the hibernating (H) Arctic ground squirrel (Citellus undulatus) contains a single species of pyruvate kinase (PyK) that is distinct from the single isoenzyme of pyK observed in the non-hibernating (NH) ground squirrel, which has been previously described (Behrisch &Johnson (1974) Can. J. Biochem. 52, 547–559). The H-PyK has a pI value of 5.7 and a molecular weight of 241 000 – 243 000. Affinity of the H-PyK for the substrates phosphoenolpyruvate (PEP) and ADP is not affected by changing temperature. It is argued that this stability of the apparent Km's for substrate over a wide temperature range permits the hibernator to take advantage of the Q10 effect in maintaining a low rate of the PyK reaction. Similarly, affinity of H-PyK for the allosteric activator fructose-1,6-phosphate (FDP) and the inhibitor ATP is also conspicuously independent of temperature, suggesting a fine stoichiometry in the relative concentrations of the regulatory ligands in control of H-PyK over a wide temperature range. Further, affinity of H-PyK for the inhibitor ATP is about three- to fourfold lower than that of the NH-PyK, a condition that would favor the maintenance of a high energy charge in the hibernating liver cell. ATP apparently inhibits PyK by causing a dissociation of the enzyme molecule into two "halves" of about 110 000 molecular weight each. This dissociation is offset and reversed by FDP. Removal of the ATP by dialysis does not of itself result in a reassociation of the PyK "halves"; FDP and/or the substrates are required for the two subunits of PyK to reassociate. As the apparent Ki of H-PyK for ATP is higher than that of NH-PyK, substantially higher concentrations of ATP are required to effect the dissociation of H-PyK. Similarly, elevated concentrations of FDP are required to offset the ATP-caused dissociation of the H-PyK.Hibernating Arctic ground squirrels that are preparing to emerge finally from the hibernating state already possess substantial activities of the NH-PyK isoenzyme. This suggests that the animal "anticipates" its transition from one metabolic state from another. On the basis of these data a formal mechanism is proposed for the regulation of liver PyK in the Arctic ground squirrel in both the non-hibernating and hibernating states.


1973 ◽  
Vol 51 (11) ◽  
pp. 1551-1555 ◽  
Author(s):  
Tony C. M. Seah ◽  
A. R. Bhatti ◽  
J. G. Kaplan

At any stage of growth of a wild-type bakers' yeast, some 20% of the catalatic activity of crude extracts is not precipitable by means of antibody prepared against the typical catalase (catalase T), whose purification and properties have been previously described. Some of this catalatic activity is due to the presence of an atypical catalase (catalase A), a heme protein, with a molecular weight estimated as 170 000 – 190 000, considerably lower than that of the usual catalases (225 000 – 250 000). Preparations of catalase A were found to be homogeneous in the analytical ultracentrifuge and in polyacrylamide gel electrophoresis. Its subunit molecular weight, determined from its iron content, was 46 500, virtually the same as that of the major band obtained in gel electrophoresis in the presence of sodium dodecyl sulfate, suggesting that the native protein is tetrameric. Its specific activity is in the range of those reported for other typical catalases.


Blood ◽  
1977 ◽  
Vol 49 (1) ◽  
pp. 113-123 ◽  
Author(s):  
DW Allen ◽  
S Cadman ◽  
SR McCann ◽  
B Finkel

Abstract Normal red blood cell (RBC) membranes were compared with (1) RBC membranes from six patients with hereditary spherocytosis (HS), (2) normal membranes after hemolysis of the RBC in the presence of calcium, or (3) normal membranes after incubation of RBC for 24 hr in phosphate- buffered saline containing calcium without added glucose. When compared with normal controls, polyacrylamide gel electrophoresis with sodium dodecyl sulfate (PAGE SDS) of all three preparations showed an increase in membrane binding of globin and protein band 4.5 (60,000 molecular weight). In an attempt to identify band 4.5, 14 enzymes were assayed in the RBC membranes. Of these, catalase and lactate dehydrogenase were increased in membranes from HS RBC and from normal cells exposed to calcium. Only catalase, however, was present in sufficient quantity and had the correct subunit molecular weight on PAGE SDS and calcium- dependent membrane binding to account for an appreciable portion of 4.5. Caralase was further identified with a component of band 4.5 by double immunodiffusion using a specific anti-catalase antibody.


FEBS Letters ◽  
1970 ◽  
Vol 12 (1) ◽  
pp. 61-64 ◽  
Author(s):  
David B. Millar ◽  
Melba A. Grafius

Blood ◽  
1977 ◽  
Vol 49 (1) ◽  
pp. 113-123
Author(s):  
DW Allen ◽  
S Cadman ◽  
SR McCann ◽  
B Finkel

Normal red blood cell (RBC) membranes were compared with (1) RBC membranes from six patients with hereditary spherocytosis (HS), (2) normal membranes after hemolysis of the RBC in the presence of calcium, or (3) normal membranes after incubation of RBC for 24 hr in phosphate- buffered saline containing calcium without added glucose. When compared with normal controls, polyacrylamide gel electrophoresis with sodium dodecyl sulfate (PAGE SDS) of all three preparations showed an increase in membrane binding of globin and protein band 4.5 (60,000 molecular weight). In an attempt to identify band 4.5, 14 enzymes were assayed in the RBC membranes. Of these, catalase and lactate dehydrogenase were increased in membranes from HS RBC and from normal cells exposed to calcium. Only catalase, however, was present in sufficient quantity and had the correct subunit molecular weight on PAGE SDS and calcium- dependent membrane binding to account for an appreciable portion of 4.5. Caralase was further identified with a component of band 4.5 by double immunodiffusion using a specific anti-catalase antibody.


1975 ◽  
Vol 53 (2) ◽  
pp. 109-119 ◽  
Author(s):  
M. Kapoor

Pyruvate kinase isolated from Neurospora and purified to homogeneity has been shown to be a tetramer of molecular weight around 242 000 by gel filtration studies and 239 000 daltons by sedimentation equilibrium measurements. The monomer produced by treatment with guanidine hydrochloride is found to be 51 000–52 000 daltons by sedimentation equilibrium studies; a molecular weight of 62 000 was determined for the monomer generated by SDS treatment by electrophoresis in SDS–polyacrylamide gels. The enzyme has an isoelectric point of 6.35–6.41. Substrate saturation kinetics of PEP show a variable extent of cooperativity depending upon the buffer ions employed in the assay. ADP is the most effective phosphoryl group acceptor, GDP and IDP being poor substitutes. A divalent cation, Mg2+, is required for activity. At low concentrations, Ca2+ acts as an activator of pyruvate kinase but it is inhibitory at high concentrations. Fructose 1,6-diphosphate is the most potent allosteric activator, fructose 6-phosphate being next in order of effectiveness. Valine is a powerful inhibitor. Phenylalanine, tyrosine, and tryptophan are without any effect individually, but their simultaneous presence results in a considerable activation. Alanine does not affect this enzyme appreciably.


Parasitology ◽  
2013 ◽  
Vol 140 (7) ◽  
pp. 897-906 ◽  
Author(s):  
ANITA VERMA ◽  
MANISH K. SUTHAR ◽  
PAWAN K. DOHAREY ◽  
SMITA GUPTA ◽  
SUNITA YADAV ◽  
...  

SUMMARYGlucose-6-phosphate dehydrogenase (G6PD), a regulatory enzyme of the pentose phosphate pathway from Brugia malayi, was cloned, expressed and biochemically characterized. The Km values for glucose-6-phosphate and nicotinamide adenine dinucleotide phosphate (NADP) were 0·25 and 0·014 mm respectively. The rBmG6PD exhibited an optimum pH of 8·5 and temperature, 40 °C. Adenosine 5′ [γ-thio] triphosphate (ATP-γ-S), adenosine 5′ [β,γ-imido] triphosphate (ATP-β,γ-NH), adenosine 5′ [β-thio] diphosphate (ADP-β-S), Na+, K+, Li+ and Cu++ ions were found to be strong inhibitors of rBmG6PD. The rBmG6PD, a tetramer with subunit molecular weight of 75 kDa contains 0·02 mol of SH group per mol of monomer. Blocking the SH group with SH-inhibitors, led to activation of rBmG6PD activity by N-ethylmaleimide. CD analysis indicated that rBmG6PD is composed of 37% α-helices and 26% β-sheets. The unfolding equilibrium of rBmG6PD with GdmCl/urea showed the triphasic unfolding pattern along with the highly stable intermediate obtained by GdmCl.


1970 ◽  
Vol 120 (2) ◽  
pp. 425-432 ◽  
Author(s):  
A. P. Fletcher ◽  
A. Neuberger ◽  
Wendy A. Ratcliffe

1. Subunit molecular weights of 76000–82000 were obtained for native and alkylated Tamm–Horsfall glycoprotein by gel filtration on Sephadex G-200 in the presence of sodium dodecyl sulphate. 2. A further estimate of the subunit molecular weight of 79000±4000 was obtained by disc gel electrophoresis in sodium dodecyl sulphate. 3. A minimum value of the chemical molecular weight of 79000±6000 was obtained from the number of N-terminal amino acids released by cyanogen bromide cleavage of the glycoprotein. 4. Similar values were obtained for the subunit molecular weight of Tamm–Horsfall glycoprotein from patients with cystic fibrosis. 5. On ultracentrifugation both in 1.0% sodium dodecyl sulphate and in 70% formic acid, Tamm–Horsfall glycoprotein sedimented as a single component, slightly faster than serum albumin. 6. On reduction of the disulphide bonds the same subunit molecular weight was obtained, which suggested that these bonds are intrachain.


Sign in / Sign up

Export Citation Format

Share Document