PubMed Health⌕ Search

Biomedical subjects

F B Rudolph

Publications and source records attributed to F B Rudolph.

At least 19 recordsLinked to original sources
PubMed1979

Effect of anthraquinone dyes and evaluation of the kinetic mechanism of yeast phosphoglycerate kinase.

Cibacron Blue 3G-A (CB3G-A, I) was investigated as a ternary complex analogue of lactate dehydrogenase and phosphoglycerate kinase as had been suggested earlier (Stellwagen, E. (1977) Accts. Chem. Res. 10, 92-98). CB3G-A and Procion Brilliant Blue (PBB, II), a structural isomer of the Cibacron dye without the sulfonated benzoyl moiety, were attached covalently to Sepharose CL-6B. The two enzymes were adsorbed to the columns and then eluted by substrates in various combinations. CB3G-A and PBB interact similarly with the two enzymes in spite of the structural differences between the dyes indicating that the specific structure of CB3G-A is not a ternary complex analogue. Inhibition studies of phosphoglycerate kinase by CB3G-A suggest that 2 molecules of dye bind per monomer and are consistent with multiple substrate binding sites. It is suggested that the kinetic mechanism of phosphoglycerate kinase is best described as steady state random.

Anthraquinones↗
PubMed1979

Biosynthesis of the pyrimidine moiety of thiamin in Escherichia coli: incorporation of stable isotope-labeled glycines.

Methods are described for the cleavage, extraction, and subsequent gas chromatographic-mass spectrometric analysis of the pyrimidine moiety of thiamin as 2-methyl-4-amino-5-[(ethylthio)methyl]pyrimidine. The methods are of a general nature and can be applied to any system. Using these methods to evaluate the incorporation of 13C-, 15N-, and 2H-labeled glycines into the pyrimidine moiety of thiamin by Escherichia coli, we established that the nitrogen and carbon atoms of glycine are incorporated as a unit into the pyrimidine. 13C- and 15N-labeled glycines are incorporated at greater than 60% but deuterium from [2-(2)H2]glycine was incorporated at only 18%. A detailed analysis of the mass fragmentation pattern of the pyrimidine derivative has established that the glycine nitrogen atom supplies the N-1 of the pyrimidine and that the C-1 and C-2 of the glycine supplies the C-4 and C-6 of the pyrimidine, respectively. This evidence is consistent with the substitution of a C2 unit between the C-5 and C-4 of the 4-aminoimidazole ribonucleotide precursor during the biosynthesis of the pyrimidine moiety of thiamin in E. coli.

Carbon Isotopes↗
PubMed1979

Purine biosynthesis in Helix aspersa: metabolic fate of labelled precursors.

1. The hepatopancreas of terrestial snails actively synthesizes purines from labelled formic acid. 2. The guanine nucleotides are initially labelled to the highest specific activity followed by adenine and hypoxanthine. 3. The labelling patterns suggest that uric acid synthesis is the primary catabolic process for nitrogen excretion while guanine excretion is due to an inability to reutilize the base.

Animals↗
PubMed1977

Effect of CrATP on the association of the reacting forms of yeast hexokinase.

Reacting enzyme sedimentation studies have been performed with yeast hexokinase isozymes A and B in the presence and absence of chromium ATP at pH 6.75. Preincubation of either isozyme with CrATP causes a shift in the monomer-dimer equilibrium toward the monomeric form. The results are consistent with the observed increase in inhibition caused by CrATP (Danenberg, K.D., and Cleland, W.W. (1975) Biochemistry 14, 28-39) being due to a conformational change in the protein which causes a decrease in the association constant for the monomer.

Adenosine Triphosphate↗
PubMed1977

The catalytic activity of monomeric yeast hexokinase A.

It has been suggested [Williams, D.C. & Jones, J.G. (1976) Biochem. J. 155, 661-667] that monomeric hexokinase isoenzyme A is not catalytically active. We here present data from reacting-enzyme sedimentation, dissociation experiments and from previous studies which are consistent with the monomeric form possessing catalytic activity.

Catalysis↗
PubMed1977

Regulation of purine metabolism: a comparative study of the kinetic properties of adenylosuccinate synthetases from various sources.

1. Adenylosuccinate synthetase has been partially purified from rat liver, fetal rat liver, Novikoff ascites cells, Walker carcinoma 256 solid tumors, chicken liver and muscle, rabbit muscle and pig brain. 2. Considerable differences exist in Michaelis constants among the various species and the changes possibly reflect differences in regulation. 3. The kinetic properties of the enzyme are generally consistent with proposed metabolic roles in various tissues.

Adenylosuccinate Synthase↗
PubMed1976

Interaction of tetraiodofluorescein with yeast hexokinase.

The dye tetraiodofluorescein (TIF) was found to be an effective inhibitor of yeast hexokinase. It is a competitive inhibitor relative to MgATP2- and a noncompetitive inhibitor of glucose binding, a kinetic pattern consistent with the previously proposed random kinetic mechanism. TIF interacts directly with the native dimeric protein to give a difference spectrum with a maximum at 543 nm. Monomeric protein (produced by addition of 0.6 M NaCl) interacts with TIF to give a slightly altered difference spectrum, with the gammamax at 545 nm. The difference spectrum of the dimeric form is not perturbed by the addition of substrates but the absorbance with the monomer is lowered by MgATP2-. The Kd for MgATP2- was estimated to be 7 nM for monomeric hexokinase. These results suggest that results of previous binding studies with hexokinase at high concentrations which have been interpreted as being at variance with kinetic studies are due likely to different conformations of the protein under different experimental conditions.

Adenosine Triphosphate↗