5-Phosphoribosyl pyrophosphate synthetase from ehrlich ascites-tumour cells: Effect of magnesium and ATP concentration on the enzymic activity

1967 ◽  
Vol 29 (4) ◽  
pp. 582-587 ◽  
Author(s):  
A.W. Murray ◽  
P.C.L. Wong
Keyword(s):  
Enzymic Activity ◽  
Tumour Cells ◽  
Phosphoribosyl Pyrophosphate ◽  
Ascites Tumour ◽  
Atp Concentration ◽  
Ehrlich Ascites ◽  
Ehrlich Ascites Tumour ◽  
Ascites Tumour Cells ◽  
Phosphoribosyl Pyrophosphate Synthetase ◽  
Ehrlich Ascites Tumour Cells

scholarly journals Analogues of ribose 5-phosphate and 5-phosphoribosyl pyrophosphate. The preparation and properties of ribose 5-phosphorothioate and 5-phosphoribosyl 1-methylenediphosphonate

1969 ◽  
Vol 112 (5) ◽  
pp. 741-746 ◽  
Author(s):  
A. W. Murray ◽  
P. C. L. Wong ◽  
Beverly Friedrichs
Keyword(s):  
Tumour Cells ◽  
Hypoxanthine Phosphoribosyltransferase ◽  
Adenine Phosphoribosyltransferase ◽  
Phosphoribosyl Pyrophosphate ◽  
Ascites Tumour ◽  
Ehrlich Ascites ◽  
Ehrlich Ascites Tumour ◽  
Ascites Tumour Cells ◽  
Phosphoribosyl Pyrophosphate Synthetase ◽  
Ehrlich Ascites Tumour Cells

1. 5-Phosphoribosyl 1-methylenediphosphonate was isolated after reaction of ribose 5-phosphate and O-adenylyl methylenediphosphonate with 5-phosphoribosyl pyrophosphate synthetase from Ehrlich ascites-tumour cells. 2. The analogue reacted with adenine phosphoribosyltransferase, hypoxanthine phosphoribosyltransferase and nicotinamide phosphoribosyltransferase [Km (analogue)/Km (5-phosphoribosyl pyrophosphate) 0·17, 0·19 and 6·3 respectively; Vmax. (analogue)/Vmax. (5-phosphoribosyl pyrophosphate) 0·011, 0·26 and 1·1 respectively]. 3. The analogue was not a substrate for 5-phosphoribosyl pyrophosphate amidotransferase or orotate phosphoribosyltransferase. 4. Ribose 5-phosphorothioate was synthesized by allowing ribose to react with thiophosphoryl chloride in triethyl phosphate. The analogue was a substrate for 5-phosphoribosyl pyrophosphate synthetase from Ehrlich ascites-tumour cells. When this reaction was coupled to either adenine phosphoribosyltransferase or hypoxanthine phosphoribosyltransferase, adenosine 5′-phosphorothioate or inosine 5′-phosphorothioate was formed respectively.

scholarly journals Some properties of adenosine kinase from Ehrlich ascites-tumour cells

1968 ◽  
Vol 106 (2) ◽  
pp. 549-555 ◽  
Author(s):  
A. W. Murray
Keyword(s):  
Maximum Velocity ◽  
Enzymic Activity ◽  
Tumour Cells ◽  
Adenosine Kinase ◽  
Ascites Tumour ◽  
Ehrlich Ascites ◽  
Ehrlich Ascites Tumour ◽  
Ascites Tumour Cells ◽  
Ehrlich Ascites Tumour Cells

1. Adenosine kinase was measured in dialysed extracts from Ehrlich ascites-tumour cells by a chromatographic procedure. 2. In the absence of added Mg2+ the Km values for ATP and adenosine were 0·22mm and 2·8μm respectively. 3. The maximum velocity of adenosine kinase with free ATP was about three times that with the Mg2+–ATP complex. Free Mg2+ was a non-competitive inhibitor of the reaction. A small amount of added Mg2+, Mn2+ or Ca2+ was required for maximum adenosine kinase activity after cation bound to the enzyme had been released by treatment with p-chloromercuribenzoate and then removed by dialysis. 4. GTP, ITP, deoxy-ATP, deoxy-GTP, CTP, xanthosine triphosphate, UTP and thymidine triphosphate could partially or completely replace ATP as a phosphate donor. 5. The reaction of ATP with adenosine kinase was competitively inhibited by AMP, GMP, IMP, ADP, deoxy-ADP and IDP (Ki 0·2, 1·1, 5·9, 1·2, 0·5 and 0·78mm respectively). Enzymic activity was markedly affected by the relative concentrations of AMP, ADP and ATP in assay mixtures. 6. The results are discussed in terms of possible mechanisms regulating the rate of adenosine kinase in vivo.

scholarly journals The transport and oxidation of succinate by Ehrlich ascites-tumour cells

1976 ◽  
Vol 160 (1) ◽  
pp. 121-123 ◽  
Author(s):  
T L Spencer
Keyword(s):  
Ph Dependence ◽  
Organic Anion ◽  
Tumour Cells ◽  
Cell Integrity ◽  
Carrier System ◽  
Ascites Tumour ◽  
Ehrlich Ascites ◽  
Ehrlich Ascites Tumour ◽  
Ascites Tumour Cells ◽  
Ehrlich Ascites Tumour Cells

The transport and oxidation of succinate by functionally intact Ehrlich ascites-tumour cells was investigated. On the basis of pH dependence and inhibitor sensitivity it was concluded that succinate may be transported across the cell membrane by the organic anion carrier system. Thus the ability of isolated Ehrlich cells to oxidize succinate is real, and is not necessarily a result of damage to cell integrity.

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