Cyanamide is a prebiotically plausible compound that has previously been invoked as a phosphate activating agent. However, its reactions with phosphate monoesters are very slow and tend to be low yielding. We now report a fast and efficient phosphate activation reaction using cyanamide in the presence of glyoxylate or pyruvate. These simple 2-oxoacid salts are shown to function as catalysts and...

The cellular distribution of hexokinase isoenzymes, N-acetylglucosamine kinase and pyruvate kinases in rat liver was studied. Hepatocytes and non-parenchymal cells with high viability and almost no cross-contamination were obtained by perfusion in situ of the liver with collagenase, with the use of an enriched cell-culture medium in all steps of cell isolation. Separation of hexokinase isoenzym...

A possible function for the alternative (nonphosphorylating) pathway is to stabilize the reduction state of the ubiquinone pool (Qr/Qt), thereby avoiding an increase in free radical production. If the Qr/Qt were stabilized by the alternative pathway, then Qr/Qt should be less stable when the alternative pathway is blocked. Qr/Qt increased when we exposed roots of Poa annua (L.) to increasing co...

2-Oxoisovalerate palmitoylcarnitine and 2-oxoisovalerate were 1 .O, 0.3 and 0.07 respectively. The rate of oxidation of 2-oxoisovalerate determined spectrophotometrically was about 12 times faster than when measured at 30°C by "CO, release from 2-0xo[ 114C]isovalerate by rat liver mitochondria1 fractions (Bremer & Davis, 1978; Patel et al., 1980). a-Cyano-4-hydroxycinnamate specifically inhibit...

OBJECTIVE & METHOD A dimeric form of pyruvate kinase isoenzyme (tumour M2-PK) is predominantly found in highly proliferating cells. Sandwich ELISA with monoclonal antibodies against dimeric (tumour) M2-PK was used to measure faecal tumour M2-PK in; 13 controls, 10 patients with colonic polyps and 32 patients with colorectal cancer. RESULTS Levels of faecal tumour M2-PK were higher in patients...

Vibrio parahaemolyticus is known to exist in a viable but nonculturable state when incubated at low temperature under starvation. It has long been debated whether the culturable cells which appear after temperature upshift are the result of true resuscitation or regrowth of a few residual culturable cells. Starved V. parahaemolyticus cells at 4 degrees C reached the nonculturable stage in about...

The crystal structure of pyruvate phosphate dikinase, a histidyl multiphosphotransfer enzyme that synthesizes adenosine triphosphate, reveals a three-domain molecule in which the phosphohistidine domain is flanked by the nucleotide and the phosphoenolpyruvate/pyruvate domains, with the two substrate binding sites approximately 45 angstroms apart. The modes of substrate binding have been deduced...

Cortisol markedly suppressed in vitro utilization of uridine-3 H by corticoid-sensitive mouse lymphoma P1798 cells. Corticoid-resistant cells were not affected. Inhibition did not depend on reduced uptake of exogenous carbohydrate precursors since similar effects were obtained in glucose-free, pyruvate-free medium. Omission of glucose and pyruvate per se did not influence uridine-3H uptake and ...

Pyruvate, malate, and succinate are the main substrates for bacteroid respiration; oxygen uptake can be inhibited by rotenone and antimycin A, but not by cyanide. The symbionts displayed limited growth and survival for over 80 days in a medium with succinate and pyruvate as main substrates, and supplemented with nucleotides. It was not possible to cultivate the endosymbionts of G. morsitans and...

The red-colored flavin anion radical of lactate oxidase was formed by photochemical reduction. The radical was found to be reoxidized readily by molecular oxygen, with a rate constant of 4 X lo5 M "I min" at pH 7.0, 25°C. On mixing the radical under anaerobic conditions with pyruvate, a change in spectrum typical of charge transfer interaction was found. The complex was composed of 1 eq of pyru...