Competitive inhibition of a glutamate carboxypeptidase by phosphonamidothionate derivatives of glutamic acid.

Several N-thiophosphonyl-glutamates were found to be potent competitive inhibitors of a zinc-dependent glutamyl hydrolase, carboxypeptidase G (CPG). Weak inhibition exhibited by an analogous N-phosphonyl-glutamate suggests that the enhanced potency of the phosphonamidothioates is due to the presence of their sulfur ligand and its favorable interactions with active site features, presumably zinc(II).     

Winter sediment resuspension in McMurdo Sound,Antarctica, and its ecological implications

Summary Sediment resuspension is a common phenomenon whose importance may be magnified in nearshore environments surrounding Antarctica, especially during the austral winter. Analyses suggest that sediments in the vicinity of McMurdo Station contain viable algal material throughout this period of darkness. The resuspension of these sediments, shown by sediment trap collections and underwater observations, would introduce organics into the water column and may provide an alternative food source for planktonic herbivores inhabiting near-shore environments during the Antarctic winter.     

A general high-performance liquid chromatography-based assay for the hydrolysis of N-acyl glutamates.

A rapid and simple HPLC assay has been developed to separate and quantify N-acyl glutamates and the corresponding carboxylic acids of the acyl moiety. This method was specifically developed to assay hydrolytic activity for glutamate carboxypeptidases. Although established assays for specific substrates of such enzymes exist, they may not be amenable for examining the hydrolytic activity of new substrate probes. This assay was developed to accommodate such probes.