Braunstein, Alexander

Reproductive Toxicity. Human data on reproductive toxicity come from observations in occupational cohorts (Alexander et al. 1996 Assennato et al. 1987 Baghurst et al. 1987 Bonde and Kolstad 1997 Braunstein et al. 1978 Chowdhury et al. 1986 Cullen et al. 1984 Gennart et al. 1992b ... 

The phosphate ester of the aldehyde form of vitamin B6, pyridoxal phosphate (pyridoxal-P or PLP), is required by many enzymes catalyzing reactions of amino acids and amines. The reactions are numerous, and pyridoxal phosphate is surely one of nature s most versatile catalysts. The story begins with biochemical transamination, a process of central importance in nitrogen metabolism. In 1937, Alexander Braunstein and Maria Kritzmann, in Moscow, described the transamination reaction by which amino groups can be transferred from one carbon skeleton to another.139 140 For example, the amino group of glutamate can be transferred to the carbon skeleton of oxaloacetate to form aspartate and 2-oxoglutarate (Eq. 14-24). 

Transamination and the Integrative Functions of the Dicarboxylic Acids in Nitrogen Metabolism Alexander F. Braunstein... 

In 1937, Alexander E. Braunstein (1902-86), working in Moscow, was studying the metabolism of glutamate in muscles and made the interesting observation that when glutamate levels decrease so do lactate (anaerobic conditions) or pyruvate (aerobic conditions). In each case the concentrations of alanine increase. He had discovered the reversible transamination reactions that connect the intermediary metabolisms of proteins and carbohydrates. 

The conversion of pyridoxal to pyridoxamine in heat-sterilized media was confirmed to be due to the reaction of pyridoxal with amino acids (Snell 1945). This was the first discovery of nonenzymatic transamination. The transamination reaction in animal tissues was first discovered in 1937 by Alexander Braunstein and associates as an amino group transfer between glutamate and alanine in pigeon muscle extract (Braunstein 1939). Irwin Gunsalus and associates showed that the tyrosine decarboxylase activity of S. faecalis was... 

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