The Kinetics of Selective Biological Transport: V. Further Data on the Erythrocyte-Monosaccharide Transport System

Measurements of the rate of loss of sugar from human erythrocytes into sugar-free solutions were made as a function of sugar concentrations. The half-saturation concentration of this process was found to be different from those half-saturation concentrations previously measured by other methods. These data, together with a number of similar data from former publications, are summarized in tabular form and their use in assessing postulated transport mechanisms is illustrated by consideration and rejection of a mechanism in which the transport process is assumed to be the result of a protein conformational change.     

Book reviews

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Book reviews

     

Use of phosphorus oxychloride in synthesizing nucleotides and oligonucleotides

Procedures are described for phosphorylating protected nucleotides, oligonucleotides and phosphoramidate oligonucleotide derivatives at the 3′-hydroxyl group. The conditions (phosphorylation with phosphorus oxychloride and pyridine in dioxane followed by hydrolysis with aqueous pyridine) are sufficiently mild that base labile (trifluoroacetylamino; β-cyanoethyl phosphotriester) and acid labile (O-monomethoxytrityl; phosphoramidate) functions are retained intact. Application of the technique is illustrated by the synthesis of dpT, dTp, d(CF₃CONH)Tp, dTp_NTp, and dTp_NTp_NTp. In addition, the utilization of phosphorus oxychloride in joining thymidine derivatives and dinucleoside phosphotriester blocks via phosphodiester links is described.     

The corrected nucleotide sequence of yeast leucine transfer ribonucleic acid

The nucleotide sequence of “Renaturable” leucine transfer RNA from Baker's yeast has been re-investigated. The results showed that (i) this tRNA has a sequence of DCD at positions 19–21, (ii) it has an anticodon m⁵CAA and (iii) it has a pseudouridine at position 40.