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Biomedical subjects

C Chen

Publications and source records attributed to C Chen.

At least 1,333 records · Page 74Linked to original sources

Ring hydroxylation of di-t-butylhydroxytoluene by rat liver microsomal preparations.

3,5-Di-t-butylhydroxytoluene (compound I) was converted into 4-hydroperoxy-4-methyl-2,6-di-t-butylcyclohexa-2,5-dienone (compound II), 4-hydroxy-4-methyl-2,6-di-t-butylcyclohexa-2,5-dienone (compound III) and 2,6-di-t-butyl-4-hydroxymethylphenol (compound IV) by rat liver microsomal preparations in the presence of NADPH and air. The oxidation of compound (I) by m-chloroperbenzoic acid also produced the same compounds. These results suggest that hydroperoxide can be an intermediate in aromatic hydroxylation and that biological oxygenations resemble per-acid reactions.

Air↗

Purification and characteristics of pyocin B39 II. Physical and chemical properties.

A purified preparation of pyocin B39 was shown to be homogeneous by disc electrophoresis and ultracentrifugation. Pyocin B39 is an antibacterial agent, protein in nature, and is capable of inhibiting the growth of susceptible cells. It caused a susceptible strain of Pseudomonas aeruginosa to release ultraviolet-absorbing material. Pyocin B39 appears to be a protein with a high molecular weight; its sedimentation coefficient is 32.8S. It was destroyed by 7 m urea but was resistant to attack by proteolytic enzymes, such as pepsin and trypsin. From its sedimentation coefficient, a molecular weight of about 2 x 10(6) was calculated. An electron photomicrograph of pyocin B39 revealed it as a rodlike particle, 7.50 pm long and 1.08 pm wide, with striations running at nearly right angles to the axes of the particle.

Bacteriocins↗