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E B Chain

Publications and source records attributed to E B Chain.

At least 19 recordsLinked to original sources
PubMed1975

Purification of D-alanine carboxypeptidase from Escherichia coli B on a penicillin-Sepharose column.

1. A soluble D-alanine carboxypeptidase from Escherichia coli strain B was purified on a p-aminobenzylpenicillin-Sepharose column. This one-step chromatography followed by an (NH4)2SO4 precipitation yielded an enzyme purified 1200-fold and some of its properties are reported. 2. The pure D-alanine carboxypeptidase was devoid of D-alanine carboxypeptidase II activity and migrated as a single protein band on analytical disc gel electrophoresis. 3. Triton X-100 in the purification procedure is an absolute requirement for obtaining a stable enzyme. 4. The enzymic activity of D-alanine carboxypeptidase was greatly affected in solution of high salt concentrations and varied somewhat with the nature of the cation tested.

Alanine↗
PubMed1974

Antiviral activity of N-phenyl-N'-aryl- or alkylthiourea derivatives in Coxsackie virus infections in mice.

The effect of five derivatives of N-phenyl-N'-aryl- or alkylthiourea-inhibitors of the multiplication of Coxsackie virus B1 and other picornaviruses in vitro-was tested in experimental infections with Coxsackie viruses B1, B3, A6, and A7 in newborn mice. Under the action of N-phenyl-N'-3-hydroxyphenylthiourea (no. 23) and N-phenyl-N'-4-carboxy-5-hydroxyphenylthiourea (no. 20) a two- to threefold reduction in mortality was observed, as well as an appreciable delay in the course of the disease (mean effective dose, lengthening by 2 to 6 days) after infection with Coxsackie viruses B1, B3, and A7. The infection with Coxsackie virus A6 was affected only by compound no. 23 and, at that, to a low degree. If the antiviral effect is to be obtained, the compounds must be applied daily (once subcutaneously) from the 24th to the 144th h after virus inoculation, a period which corresponds to the incubation period and the beginning of the manifested infection. On the basis of these data, as well as of the relatively high selectivity (therapeutic index of 3 to 20), the two indicated substances may be considered to be reliable antiviral chemotherapeutic agents.

Animals↗
PubMed1973

Protein synthesis by perfused hearts from normal and insulin-deficient rats. Effect of insulin in the presence of glucose and after depletion of glucose, glucose 6-phosphate and glycogen.

In the absence of glucose, insulin stimulated the incorporation of (14)C-labelled amino acids into protein by perfused rat hearts that had been previously substantially depleted of endogenous glucose, glucose 6-phosphate and glycogen by substrate-free perfusion. This stimulation was also demonstrated in hearts perfused with buffer containing 2-deoxy-d-glucose, an inhibitor of glucose utilization. It is concluded that insulin exerts an effect on protein synthesis independent of its action on glucose metabolism. Streptozotocin-induced diabetes was found to have no effect either on (14)C-labelled amino acid incorporation by the perfused heart or on the polyribosome profile and amino acid-incorporating activity of polyribosomes prepared from the non-perfused hearts of these insulin-deficient rats, which show marked abnormalities in glucose metabolism. Protein synthesis was not diminished in the perfused hearts from rats treated with anti-insulin antiserum. The significance of these findings is discussed in relation to the reported effects of insulin deficiency on protein synthesis in skeletal muscle.

Animals↗
PubMed1973

Biosynthesis of ergotamine by Claviceps purpurea (Fr.) Tul.

High-yielding strains of Claviceps purpurea (Fr.) Tul, grown on a defined medium, have been used for a study of the biosynthesis of the peptide ergot alkaloid, ergotamine. l-[U-(14)C]tryptophan, dl-[2-(14)C]mevalonic acid lactone, sodium [2-(14)C]acetate, sodium [(14)C]formate and the methyl group of l-[methyl-(14)C]methionine were efficiently incorporated into the peptide alkaloids and specifically labelled the ergoline moiety of ergotamine. These results are the same as previously found for the biosynthesis of other ergot alkaloids. Time-course incubation experiments demonstrated that l-[U-(14)C]phenylalanine, l-[U-(14)C]proline and l-[U-(14)C]alanine were incorporated into the peptide ergot alkaloids. Chemical degradation of the radioactive alkaloid derived from additional precursor incubation experiments showed that phenylalanine and proline function as the most efficient precursors, and specifically label the constitutive side-chain phenylalanyl and prolyl moieties of the alkaloid. The evidence obtained from l-[U-(14)C]alanine-incorporation experiments was inconclusive. However, degradation of ergotamine isolated after incubation with dl-[1-(14)C]alanine, showed that the carboxyl group of the labelled amino acid was specifically incorporated into the alpha-hydroxy-alpha-amino acid residue of the alkaloid. This, in conjunction with the l-[U-(14)C]alanine-incorporation results, showed conclusively that all three carbon atoms of alanine were incorporated as a biosynthetic unit into the alpha-hydroxy-alpha-amino acid moiety of ergotamine.

Acetates↗