Multiple adenosine deaminases in the frog (Rana catesbeiana)

Pang, F.; Fisher, James R.

doi:10.1016/0010-406x(68)90756-1

Cited by 39 publications

(10 citation statements)

References 11 publications

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“…Chilson and Fisher [3], Brady and O'Donovan [1], and Ma and Fisher [17] reported species differences in the enzyme properties. Specific tissue differences of adenosine deaminase were also found by Fisher et al [5] and by Ma and Fisher [15,16] …”

Section: Introductionsupporting

confidence: 56%

Temperature Conversion Factors, Activation Energy, Relative Substrate Specificity and Optimum pH of Adenosine Deaminase from Human Serum and Tissues

Giusti¹,

Gakis²

1971

Enzyme

124

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Some properties of human serum and human tissue adenosine deaminase have been studied. Normal and pathological human serum adenosine deaminase and normal human tissue adenosine deaminase show the same activation energy values which are different from those found for the calf intestine enzyme. In the human species, but not in the bovine species, the serum enzyme differs from the tissue enzyme in pH optimum and relative substrate specificity for adenosine and 2’deoxyadenosine. Temperature conversion factors for human serum and calf intestine adenosine deaminase have also been calculated.

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Section: Introductionsupporting

confidence: 56%

Temperature Conversion Factors, Activation Energy, Relative Substrate Specificity and Optimum pH of Adenosine Deaminase from Human Serum and Tissues

Giusti¹,

Gakis²

1971

Enzyme

124

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“…Molecular weight as determined by gel chromatography of both crude haemolysates and purified preparations from types 1, 2 and 2-1 erythrocytes was in the range of 30000-35000. Recent reports (Ma & Fisher, 1968;Akedo et al, 1972) suggest that adenosine deaminase from a variety of sources exists in both highand low-molecular-weight forms. The possible existence of a monomer-polymer relationship between the isoenzyme forms of the enzyme from human erythrocytes was investigated in crude haemolysates by the method of Smithies (1962).…”

Section: Molecular Weightsmentioning

confidence: 99%

Partial purification and properties of the common inherited forms of adenosine deaminase from human erythrocytes

Osborne

Sṕencer

1973

Biochemical Journal

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1. The partial purification of adenosine deaminase, types 1, 2 and 2-1, from human erythrocytes is described. 2. The isoenzyme components characteristic of the three forms of the enzyme were partially resolved by chromatography on DEAE-Sephadex. 3. Gel chromatography of the various forms of the enzyme gave estimates of the molecular weights in the range 30000-35000. 4. Electrophoresis in starch gels containing increasing percentages of starch did not reveal any differences in molecular weight between the genetic variants or their isoenzyme components. 5. Analytical isoelectric-focusing experiments in polyacrylamide gels gave the following pI values for the four isoenzyme components present in type 2-1 erythrocytes: 4.70, 4.83, 4.94 and 5.06. 6. All forms of the enzyme gave K(m) values for adenosine of about 30mum and K(i) values of about 8mum for the competitive inhibitor purine riboside. 7. Reaction rates of the type 1 and 2 enzymes were measured at different temperatures. Both enzymes gave values for the energy of activation for hydrolysis of adenosine of about 33.4kJ/mol (8kcal/mol). 8. Heat inactivation of all forms of the enzyme was markedly dependent on ionic strength, the rate of inactivation increasing with increasing ionic strength. The type 1 and type 2 forms of the enzyme differed significantly in their susceptibility to heat inactivation. From the variation of rates of inactivation with temperature, values were obtained for the energies of activation for the heat inactivation of both enzymes as follows: type 1 enzyme 275.5kJ/mol (65.9kcal/mol) and type 2 enzyme 241.6kJ/mol (57.8kcal/mol.).

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“…Adenosine deaminase exists in various forms, which differ in molecular weight. The small form (C form) is catalytically active and has a molecular weight of around 40,000 [Ma and Fisher, 1968a;1968bl. The C form can bind to the so-called adenosine deaminase binding protein [Andy and Kornfeld, 19821 to form a complex of molecular weight up to 200,000, which is named A form [Ma and Fisher, 1968a;1968bl.…”

Section: Introductionmentioning

confidence: 99%

“…The small form (C form) is catalytically active and has a molecular weight of around 40,000 [Ma and Fisher, 1968a;1968bl. The C form can bind to the so-called adenosine deaminase binding protein [Andy and Kornfeld, 19821 to form a complex of molecular weight up to 200,000, which is named A form [Ma and Fisher, 1968a;1968bl. Despite these facts, no work has been reported on the characterization of the enzyme from the brain, mainly because the level of the enzyme is relatively low in the brain if compared with other tissues [Centelles et al, 19871. ethanol.…”

Section: Introductionmentioning

confidence: 99%

Purification and partial characterization of brain adenosine deaminase: Inhibition by purine compounds and by drugs

Centelles

Franco

Bozal

1988

J of Neuroscience Research

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Rat brain adenosine deaminase (E.C. 3.5.4.4.) was purified 667-fold from the supernatant fraction by the following techniques: heat treatment (60 degrees C), fractionation with ammonium sulfate, column chromatography on DEAE-Sepharose, and preparative gel electrophoresis. The purified enzyme was homogeneous by the criterion of polyacrylamide disc gel electrophoresis and isoelectric focusing. Amino acid composition is given. The isoelectric point of the enzyme (5.2) was determined by isoelectric focusing on agarose. The apparent molecular weight was estimated to be 39,000 (Stokes Radius [Rs] = 27.3 A) using a calibrated Sephacryl S-300 column. The study of the influence of the temperature on the initial reaction rates allowed calculation of Ea (8.9 Kcal/mole) and delta H (5.0 Kcal/mole) values. The variation of V and Km with pH suggests the existence of a sulfhydryl group and an imidazole group in the enzyme-substrate complex. The enzyme had a Km (adenosine) of 4.5 X 10(-5) M and was inhibited by inosine, guanosine, adenine, and hypoxanthine but not by other intermediates of purine metabolism. None of the inhibitors were active as substrates. The enzyme was also inhibited by dimethyl sulfoxide and ethanol. Inhibition by ethanol can account partially for the CNS depressant effects of levels 3 and 4 of alcohol intoxication. A number of drugs having therapeutic uses such as sedative, anxiolytic, analgesic, and relaxant are modulators of the enzyme. Among these, lidoflazine, phenylbutazone, and chlordiazepoxide are the most potent as inhibitors (Ki 30, 54, and 83 microM, respectively), whereas medazepam is the most potent as activator (Ka 0.32 mM). Thus, it is concluded that some drugs that inhibit adenosine uptake also modulate adenosine deaminase activity. Besides, since the enzyme is located extracellularly [Franco et al, 1986], these drugs can modulate the physiological effects exerted by extracellular adenosine.

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Multiple adenosine deaminases in the frog (Rana catesbeiana)

Cited by 39 publications

References 11 publications

Temperature Conversion Factors, Activation Energy, Relative Substrate Specificity and Optimum pH of Adenosine Deaminase from Human Serum and Tissues

Temperature Conversion Factors, Activation Energy, Relative Substrate Specificity and Optimum pH of Adenosine Deaminase from Human Serum and Tissues

Partial purification and properties of the common inherited forms of adenosine deaminase from human erythrocytes

Purification and partial characterization of brain adenosine deaminase: Inhibition by purine compounds and by drugs

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