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A Darbre

Publications and source records attributed to A Darbre.

5 recordsLinked to original sources

Studies on sequencing of peptides from the carboxyl terminus by using the thiocyanate method.

We report on our experience in applying the thiocyanate method developed by Stark (1968) (Biochemistry 7, 1796-1807) to the sequencing of short peptides from the carboxyl end in free solution. Yields fell to very low levels after three cycles of degradation. The method was time-consuming because of the filtration and freeze-drying stages involved. To overcome these problems, peptides were attached to modified polystyrene polymers for sequential degradation in the solid phase, and a maximum of six amino acids was determined. Also, ribonuclease was attached to active-ester glass beads and sequential degradation was carried out to determine six amino acids at the C-terminal end of this protein.

Amino Acid Sequence

Amino acids attached to transfer ribonucleic acid in vivo.

1. tRNA was extracted from rabbit liver by both the phenol and diethyl pyrocarbonate methods under conditions preventing deacylation of the amino acids attached in vivo. 2. After deacylation 12 amino acids were determined by gas-liquid chromatography, by using the flame-ionization and nitrogen-sensitive thermionic detectors. 3. Comparison of the distribution of 12 amino acids attached to tRNA with those contained in total tissue protein and in the free pool showed little correlation. 4. Results for the enzymic charging assay for tRNA in vitro did not correlate satisfactorily with the analysis of amino acids attached to tRNA in vivo. Marked differences were ntoed in comparison made between our own and other published results.

Amino Acids