Biomedical subjects

A M Westley

Publications and source records attributed to A M Westley.

3 recordsLinked to original sources

PubMed1996

Enzyme inhibition in open systems. Superiority of uncompetitive agents.

Investigations of the open system behavior of reversible dead-end inhibitors were carried out by means of computer simulations and experimental studies. The results from both approaches indicate that substrate-competitive inhibition may often be an inappropriate basis for design of potential therapeutic agents. The use of uncompetitive (also called anticompetitive) inhibitors in this role is likely to be far more effective. Chemical analogs of pathogen-specific enzymic reaction products rather than analogs of substrates provide a promising basis for the systematic design of such uncompetitive inhibitors.

Binding, Competitive↗

PubMed1991

Biological sulfane sulfur.

A voltammetric method for determining cyanide-reactive sulfane sulfur in biological materials is described. Samples are incubated with a sulfurtransferase, a thiolic cofactor, and cyanide. Thiocyanate formed and/or residual cyanide may then be determined electrochemically with either a silver rotating disk electrode or a dropping mercury electrode in differential pulse mode to provide estimates of sulfane sulfur content. The thiocyanate-based procedure is preferable, particularly when samples contain either serum albumin or inorganic sulfide.

Animals↗

PubMed1989

Voltammetric determination of cyanide and thiocyanate in small biological samples.

Practical methods for the quantitative measurement of cyanide and thiocyanate content in small biological samples are presented. The basis of the procedures is electrochemical determination of CN- with a silver rotating disk electrode at 90 mV, relative to the Ag/AgCl reference electrode, or with a dropping mercury electrode in differential pulse mode at -240 mV. Thiocyanate is oxidized to CN- with permanganate under controlled conditions prior to its analysis. Endogenous cyanide and cyanide from SCN- oxidation are recovered, separately, by volatilization and trapping. Emphasis is placed on careful handling of specimens prior to analysis. Precautions include a provision for sequestering cyanide in storage, the use of an antioxidant, and an avoidance of the spontaneous sulfide formation from proteins that occurs in even mildly alkaline solutions.

Cyanides↗