Transaminases for Pyridoxamine and Purines

Abstract

rnethremoglobin and oxyhremoglobin can be demonstrated simply by shaking these solutions with chloroform, when only the former is denatured and is precipitated. When the water molecule bound to iron in methremoglobin is replaced by fluoride or azide ions, however, tho pigment acquires resistance to chloroform treatment. These results are exactly parallel to those observed in the desiccation experiments, which demornitrated an increased resistance of hmmoglobin and methromoglobin to denaturation when their iron-bound water molecules are replaced by oxygen, f-Ju01•ido or azi(le.Tho reactions taking place during the cfrying of Ju:emoglobin and methoomoglobin, although perfectly reversible, appear to be of a more complex nature than the simple polymerimtion envisaged by Haurowitz 2 , and to involve reversible changes in tht, architecture of the whole hrornoprotein molecul0.

Adenosine deaminase and ribosidase in spores of Bacillus cereus

“…An ethanol-precipitated deaminase preparation from 1010 spores in 1 ml. of reaction mixture was tested for transaminase activity, the test system of Gunsalus & Tonzitich (1952) being used with adenosine as the amino-donor. After protein precipitation with 2-5 % HC104, paper chromatograms were run in collidine-lutidine.…”

The genome sequence of E. coli W (ATCC 9637): comparative genome analysis and an improved genome-scale reconstruction of E. coli

“…Among thousands of isolates, only four strains (the common laboratory strains K-12, B, C, and W) and their derivatives are designated as Risk Group 1 organisms in biological safety guidelines [1,2]. A fifth strain, E. coli Crooks (ATCC 8739), has also been used extensively in laboratories for over 70 years [3-5]; more recently, it has been used as a host for industrial biochemical production [6-8]. There have been no reported cases of the strain being pathogenic, suggesting that it is generally safe.…”

Purine and pyrimidine transaminases in Escherichia coli

“…Just before use, weighed amounts of the dried cells were suspended in water or in phosphate buffer and used without further treatment. Cell-free extracts were occasionally prepared by the method of Gunsalus & Tonzetich (1952).…”

“…This reaction is not possible with an intact purine or pyrimidine ring; therefore transamination of these compounds must involve a mechanism not previously described or must be preceded by a change in the ring such as reduction. It seemed therefore of importance to repeat and to extend the experiments of Gunsalus & Tonzetich (1952). We have not been able to confirm their observations by employing similar bacteria and similar experimental conditions.…”

“…Biological conversion of amino purines and pyrimidines into their hydroxy compounds has hitherto been ascribed exclusively to the action of hydrolytic deaminases. The report that suspensions or extracts of E8cherichia coli (strains B and Crookes) catalyse transamination between x-oxoglutarate and adenine, guanine or cytosine (Gunsalus & Tonzetich, 1952) would point to the existence of important alternate metabolic pathways for these constituents of nucleic acids. The transamination reaction, as usually understood, involves an intermolecular oxidation-reduction.…”