Activation of Methionine Synthetase by a Reduced Triphosphopyridine Nucleotide-dependent Flavoprotein System

The measurement of triphosphopyridine nucleotide and reduced triphosphopyridine nucleotide and the role of hemoglobin in producing erroneous triphosphopyridine nucleotide values.

A method is described for determining TPN+ and TPNH in a single tissue homogenate made in dilute NaOH at 0’. One portion, for TPN+, is acidified after adding ascorbic acid to prevent TPNH oxidation. A second portion, for TPNH, is heated (still alkaline) after adding cysteine to prevent oxidation. If desired, a third portion can be analyzed directly without heating for total TPN (TPN+ plus TPNH)...

The aerobic oxidation of reduced triphosphopyridine nucleotide by a wheat germ enzyme system.

Demonstration of TPNH Oxidase-The rate of decrease in light absorption at 340 rnp, due to TPNH, was used as an assay for the enzyme. The test was run routinely in glycylglycine buffer of pH 7.4. The conditions are given in detail in the legend to Fig. 1. Under these circumstances, the rate of change in optical density was roughly proportional to the amount of enzyme employed, in the range A log...

Activation of human neutrophil nicotinamide adenine dinucleotide phosphate, reduced (triphosphopyridine nucleotide, reduced) oxidase by arachidonic acid in a cell-free system.

Sonicates from unstimulated human neutrophils produce no measurable superoxide since the superoxide-generating enzyme, NADPH oxidase, is inactive in these preparations. Previous attempts to activate the oxidase in disrupted cells with conventional neutrophil stimuli have been unsuccessful. This report describes a cell-free system in which arachidonic acid (82 microM) was able to activate supero...

A triphosphopyridine nucleotide dependent alcohol dehydrogenase from Leuconostoc mesenteroides.

Ethanol formation during glucose fermentation is a relatively common activity of microorganisms; a few species, including Leuconostoc mesenterodes, produce ethanol as a major fermentation end product. The significant results from experiments with various species on this subject are: (1) at least three different metabolic pathways are available for anaerobic conversion of glucose to ethanol (Kos...

Preparation of triphosphopyridine nucleotide.