PubMed Health⌕ Search

Biomedical subjects

F J Reithel

Publications and source records attributed to F J Reithel.

At least 19 recordsLinked to original sources
PubMed1977

The molecular weight of, and evidence for two types of subunits in, the molybdenum-iron protein of Azotobacter vinelandii nitrogenase.

The weight-average molecular weight of the Mo-Fe protein isolated from Azotobacter vinelandii has been determined by sedimentation-equilibrium techniques. In buffer, the value is 245000+/-5000; in 8M-urea, the value is 61000+/-1000. The protein was separated into two components by chromatography on CM-cellulose in 7M-urea, pH 4.5. These components have similar molecular weights but were shown to differ in charge, amino acid content and arginine-containing peptides. It is proposed that the tetramer has the subunit composition (nalpha2nbeta2).

Amino Acids↗
PubMed1975

The subunit structure of phosphoglucose isomerase from bakers' yeast.

Bakers' yeast phosphoglucose isomerase was studied by both chemical and physical methods to determine its submit structure. Gel filtration in 6 M guanidine HCl as well as acrylamide gel electrophoresis of sodium dodecyl sulfatedentured phosphoglucose isomerase showed two speices corresponding to one-half and one-fourth of the preparative molecular weight of 119,400 determined by equilibrium centrifugation. Further centrifugation studies showed that the enzyme could be completely dissociated to species of 30,000 molecular weight. Peptide maps of tryptic hydrolysates of denatured and chemically modified enzyme showed that the protein is composed of four identical or nearly identical sub-units. The results of amino acid analysis, except half-cystine content, were compatible with identical subunits. The appearent partial specific volume and extinction coefficient were also determined.

Amino Acid Sequence↗
PubMed1975

Evidence for an active dimer of Escherichia coli beta-galactosidase.

BETA-Galactosidase (EC 3.2.1.23), prepared from strains ML 308 and K12 3300 of Escherichia coli, dissociated into an inactive monomer in the presence of Ag+. When such a monomer preparation is treated with excess of thiol an enzymically active dimer is formed in addition to an active tetramer. It is suggested that Ag+ may be of value in studies on other multimeric proteins as a mild dissociating agent.

Dithiothreitol↗
PubMed1971

Studies on protein multimers. The association-dissociation behaviour of -galactosidase in glycerol.

1. The effect of glycerol on the association-dissociation behaviour of beta-galactosidases from Escherichia coli is described. Two strains, K12 and ML308, were used as sources of enzyme. The conditions used, involving glycerol at a concentration of 90%, result in dissociation of the active 540000-dalton form to inactive structural subunits of 135000 daltons. 2. A pH-dependent process, assumed to be cyclic in mechanism, allows reassociation to an active form indistinguishable from the initial protein. 3. The apparently identical structural subunits, if produced in the presence of EDTA, were found to give rise to two electrophoretically distinguishable species. 4. Enzymes from both strains of E. coli can be distinguished electrophoretically but exhibit the same behaviour in glycerol. 5. A scheme of the association-dissociation is presented that is consistent with the behaviour observed and that has some predictive value.

Edetic Acid↗