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Biomedical subjects

R Leberman

Publications and source records attributed to R Leberman.

At least 73 records · Page 4Linked to original sources
PubMed1976

Release of certain ribosomal proteins from 70-S Escherichia coli ribosomes by mild ribonuclease digestion.

A method for the release of some proteins from Escherichia coli (MRE 600)ribosomes is described, avoiding extraction with denaturing reagents. High-salt-washed, 70-S ribosomes were treated with pancreatic ribonuclease which led to the release of 12 proteins of the larger ribosomal subunit. Separation of released protein was first attempted by gel filtration and by fractionation with (NH4)2SO4. The number and type of the released proteins were identified by sodium dodecyl sulphate-polyacrylamide gels and two-dimensional gel electrophoresis. The method should prove of use in the large scale purification of proteins L1, L7, and L25.

Bacterial Proteins↗
PubMed1976

Elongation factor T from Bacillus stearothermophilus and Escherichia coli. Purification and some properties of EF-Tu and EF-Ts from Bacillus stearothermophilus.

Homogeneous preparations of elongation factors EF-Tu and EF-Ts from Bacillus stearothermophilus have been obtained with specific activities of 20000 +/- 2000 and 500000 +/- 50000 units/mg, respectively. By dodecylsulphate-polyacrylamide gel electrophoresis the molecular weight of EF-Tu was found to be 49000 +/- 2000 and of EF-Ts 35500 +/- 1000. Nucleotide-free EF-Tu was prepared by using ITP as a GDP-binding-site-directed analogue. EF-Tu was shown to contain two sulphydryl groups, one reacting fast and one slowly with N-ethylmaleimide and 5,5'-dithio-bis(2-nitrobenzoic acid) under non-denaturing conditions. The same reagents were shown to react with the three sulphydryl groups of EF-Ts in the native state. The heat stabilities of EF-Tu and EF-Ts are reversed with respect to the Escherichia coli factors, EF-Tu being the more stable protein; even nucleotide-free EF-Tu is relatively stable with a half-life at room temperature of about 35 h.

Amino Acids↗
PubMed1976

Multiple forms of lysyl-tRNA synthetase from Escherichia coli.

Lysyl-tRNA synthetase has been isolated from E. coli. The enzymatic activity elutes as three or four bands from a hydroxyl-apatite column. Polyacrylamide gel analysis shows that each of these bands contain more than one enzymatically active protein species. The molecular weights of the subunits of these species provides an explanation for the variation in the molecular weights previously reported for this enzyme.

Amino Acyl-tRNA Synthetases↗
PubMed1974

The fractionation of t-RNA on N,N'-bis(3-aminopropyl)-piperazine substituted-Sepharose.

An anion exchange agarose has been prepared by modifying sepharose 6B with N,N'-bis (-3-aminopropyl) piperazine. This material (BAPP-Sepharose) has been used for the fractionation of t-RNA from E.coli by column chromatography. The results obtained with gram quantities of crude t-RNA at pH 4.6 and pH 8.0 as measured by the elution patterns of alanyl, arginyl, aspartyl, leucyl, lysyl, methionyl, phenylalanyl, prolyl, seryl, tyrosyl, and valyl t-RNA are described.

Chromatography, Ion Exchange↗