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Glutaminase A isolated from Escherichia colireacts with the glutamine analogue, 6-diazo-5-oxonorleucine, in two ways: (a) it catalyzes hydrolysis of the C5—C6bond to yield glutamic acid and diazomethane; and (b) a group at the active site of the enzyme becomes irreversibly alkylated by the intact carbon chain of the analogue. The reactions are thought to occur through association of the compound with the substrate binding site followed by acid catalyzed attack of an enzyme group either at C5to yield glutamic acid and diazomethane, or at C6, to inhibit the enzyme. The ratio of rate of hydrolysis to that of alkylation is about 70. Diazomethane was identified by observing that both the reaction product from diazo-oxo[6-14C]norleucine and [14C]diazomethane itself react with water and with benzoic acid to give labeled methanol and methyl benzoate in the same ratio.

Several letters to the editor are presented in response to articles in previous issues including "All Aboard" in the August 27, 2011 issue, "The last of the gang" in the August 20, 2011 issue and one by David Garrett defending the need for longer prison sentences for recidivists in the August 20, 2011 issue.

The article presents the author's comments on a review of a book by Kapka Kassabova on tango.