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Biomedical subjects

A G Cooper

Publications and source records attributed to A G Cooper.

At least 55 records · Page 3Linked to original sources
PubMed1970

Phenothiazine-N-carbonyl chloride, a specific inactivator of chymotrypsin.

Phenothiazine-N-carbonyl chloride inactivated chymotrypsin and trypsin by means of a 1:1 stoicheiometric reaction. Its reaction with chymotrypsin was 29 times as fast as that with trypsin and was inhibited by indole. The reaction of phenothiazine-N-carbonyl chloride with chymotrypsin resembled an enzyme-substrate reaction in which the deacylation step is rate-limiting. Slow deacylation occurred, resulting in complete regeneration of active enzyme in 15h. The pH-rate profile of the inactivation process had a maximum at pH7.8. These data and other evidence indicate that the reaction of phenothiazine-N-carbonyl chloride with chymotrypsin exhibits ;kinetic specificity'. Therefore any hypothesis that attempts to describe the topography of the active site of chymotrypsin should take into account the reactivity of phenothiazine-N-carbonyl chloride. The above findings, as well as recent reports of others, are examined within the context of a hypothesis given in an earlier paper (Erlanger, 1967).

Binding Sites↗
PubMed1967

Hemagglutinating 7S subunits of 19S cold agglutinins.

Two highly purified IgM cold agglutinins have been mildly reduced yielding 7S subunits, with interchain covalent bonds intact. These subunits retained most of the cold-agglutinin activity as well as the specificity of the parent antibodies. However, as might be anticipated from theories of the importance of antibody size and number of subunits for complement binding, the IgM subunits were only very weakly lytic compared with the intact cold agglutinins. The findings are consistent with the presence of ten antibody-combining sites on the IgM molecule.

Agglutinins↗