Biochemistry of functional neural crest tumors

Bovine brain ketimine reductase

We report the purification from bovine brain of an NAD(P)H-dependent reductase which actively reduces a new class of cyclic unsaturated compounds, named ketimines. Ketimines arise from the transamination of some sulphur-containing amino acids, such as L-cystathionine, S-aminoethyl-L-cysteine and L-lanthionine. The enzyme also reduces delta 1-piperidine 2-carboxylate, the carbon analog of aminoethylcysteine ketimine. Some kinetic and molecular properties of this enzyme have been determined. Subcellular localization and regional brain distribution have also been studied. The ketimine reductase activity was found to be associated with the soluble fraction, and was located prevalently in the cerebellum and cerebral cortices. Cyclothionine and 1,4-thiomorpholine-3,5-dicarboxylic acid, the enzymatic reduction products of cystathionine ketimine and lanthionine ketimine, respectively, have been detected in bovine brain, thus suggesting a role of this enzyme in their biosynthesis.

Catecholamine measurements in phaeochromocytoma: a review

The early diagnosis of phaeochromocytoma by measurement of catecholamines or their metabolites is important, since it brings the prospect of permanent cure to a small but significant proportion of the hypertensive population. The development of sensitive and specific methods for the analysis of catecholamines has led to the increased use of such measurements in the biochemical diagnosis and localisation of this rare tumour.