Chloramphenicol: an Enzymological Microassay

An automated microassay for blood ammonia.

A microassay for blood ammonia has been developed. After dilution, blood is dialyzed by a continuous flow procedure, and the ammonium ions in the dialysate are assayed colorimetrically by the hypochlorite-phenol Berthelot reaction. Concentrations from 1 to 400 mumol/l NH+4 can be measured in a 50 mul whole blood sample. Using slight modifications, concentrations up to 800 mumol/l NH+4 can be de...

Enzymological approaches to the lipidoses.

There are now ten known heritable disorders of lipid metabolism for which the nature of the underlying enzymological defect is conclusively established. In addition to devising procedures for successful enzyme replacement therapy, much current work deals with the development of convenient, effective methods for the rapid diagnosis of patients with these disorders, the detection of heterozygous ...

Enzymological basis of nitrogen fixation

where the first is the limit chemical stoichiometry of one H2 formed for every N2 reduced. At standard state, the dintirogen reduction is exothermic and remains so at cellular concentrations with ferredoxins or flavodoxins as electron donors. Nevertheless, substrate reduction requires ATP hydrolysis where the limit stoichiometry usually is considered to be 2 ATP per electron (16 ATP total to sa...

Chloramphenicol.

In situ microassay of ornithine decarboxylase.

Ornithine decarboxylase catalyses the principal step in the biosynthesis of polyamines (1, 2) and is reported to be a proto-oncogen implicated in the control of both FIG. 1. Modified rubber stopper. cell growth and transformation (3). Its activity is induced by a number of agents such as amino acids, pharmaceuticals, hormones, and growth stimuli (4). The cient to completely cover the plated cel...