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F Dallocchio

Publications and source records attributed to F Dallocchio.

50 records · Page 3Linked to original sources
PubMed1981

[[[Purification and properties of 6-phosphogluconate dehydrogenase from human erythrocytes].

6-phosphogluconate dehydrogenase was purified from human erythrocytes by chromatography on 2'5' ADP Sepharose and ammonium sulfate precipitation, to a specific activity of 28 IU/mg of protein. The enzyme binds two NADP molecules per molecule of dimer with a Kd of 6.95 microM, or only one molecule of NADPH per molecule of dimer with a Kd of 0.38 microM. The substrate has no effect on the binding of NADPH, whereas increases the binding of a coenzyme analogue, the NADP oxidized with periodate. These findings indicate a possible regulatory role for 6-phosphogluconate dehydrogenase.

Chromatography, Affinity↗
PubMed1981

Evidence for multiple pairs of vicinal thiols in some proteins.

The oxidizing agent periodate has been used as an analogue of phosphate. The reaction of periodate with some enzymes which have a phosphate-binding site causes only the formation of disulfide bridges and the loss of the catalytic activity. Phosphate and other tetrahedral anions protect against inactivation. Other enzymes are not inactivated by periodate, which seems to be specific for vicinal thiols. The results obtained suggest (a) the use of periodate for the detection of vicinal thiols in proteins, (b) the presence of multiple pairs of vicinal thiols in the proteins tested, and (c) the presence of these pairs at a phosphate-binding site. An hypothesis on the chemical structure of the phosphate-binding site of some proteins is advanced.

Alcohol Oxidoreductases↗
PubMed1979

Affinity labelling of the NADP+-binding site of glucose 6-phosphate dehydrogenase from Candida utilis.

1. Periodate-oxidized NADP+ inhibits the catalytic activity of glucose 6-phosphate dehydrogenase from Candida utilis, competing with NADP+. 2. Incubation of the enzyme with the coenzyme analogue causes partial reversible inactivation of the enzyme as a result of affinity labelling of the coenzyme-binding site. 3. Some kinetic values of the reaction were calculated. 4. The inactivation can be made irreversible by treatment with NaBH4, which reduces a Schiff base formed between an aldehyde group on the coenzyme analogue and a lysine residue on the enzyme. 5. Complete inactivation can be correlated with the binding of only one inhibitor to each enzyme subunit. 6. The lysine residue involved in the binding of the inhibitor is present at the coenzyme-binding site.

Affinity Labels↗
PubMed1978

Alkylation of 6-phosphogluconate dehydrogenase from Candida utilis with coenzyme analogues.

The mechanism of the inactivation of 6-phosphogluconate dehydrogenase from Candida utilis with two coenzyme analogues can be differentiated on the basis of kinetic studies and of the properties of the inactivated enzyme. 3-Chloroacetylpyridine--adenine dinucleotide phosphate is clearly an affinity label and 3-choloroacetylpyridine--adenine dinucleotide a second-order reagent. For 3-chloroacetylpyridine--adenine dinucleotide phosphate, there is a loss of one thiol per subunit at complete inactivation whereas for 3-chloroacetylpyridine--adenine dinucleotide 2.7 thiol groups are lost. The fluorescence of the protein is quenched after alkylation by 3-chloroacetylpyridine--adenine dinucleotide phosphate and there is no quenching after the inactivation with 3-chloroacetylpyridine--adenine dinucleotide.

Alkylation↗
PubMedDate not supplied

Evidence for the proximity of a cysteine and a lysine residue in the active site of 6-phosphogluconate dehydrogenase from Candida utilis.

The environment of a cysteine residue in the active site of 6-phosphogluconate dehydrogenase from Candida utilis was investigated by means of N-(3-pyrene) maleimide. The reaction between enzyme and inhibitor results in the modification of one cysteine residue per enzyme subunit, and in the complete inactivation of the enzyme. In a second step, the epsilon-amino group of a lysine residue causes an intramolecular aminolysis of the bound inhibitor. These results indicate that a lysine and a cysteine residues are close in the three-dimensional structure of the active site of 6-phosphogluconate dehydrogenase.

Amino Acid Sequence↗