Oxalace tate

In the widely used colorimetric assay of SGOT and SGPT (R2), serum is incubated at 37 °G with phosphate-buffered L-aspartate/a-oxoglutarate or DL-alanine/a-oxoglutarate, respectively, the reaction terminated after a definite interval by addition of 2,4-dinitrophenylhydrazine in dilute HCl, and after a period at room temperature the hydrazones of oxalace-tate or pyruvate so formed are treated with dilute alkali and the optical density measured against water at 505 mp the results are read from standard curves of optical density against transaminase activity. 

The other two CO2 are introduced to Q-carbons of the carbonyl groups of a-keto glutarate and pyruvate to produce isocitrate and oxalace-tate, respectively ... 

A functional difference between CAM and C4-photosynthesis is the immediate source of P-enolpyruvate for carboxylation. In C -photosynthesis, it is largely assumed that PEP is regenerated from the 3-C fragment after malate (or oxalace-tate) utilization. Two possibilities seem apparent (1) pyruvate is converted to P-enolpyruvate by pyruvate, Pi dikinase (Hatch and Slack, 1970) or (2) oxalacetate rather than malate is decarboxylated to form P-enolpyruvate by PEP carboxyki-nase (Black et al, 1973). 

Condensing enzyme —condensation of acetyl CoA and oxalace-tate to form citrate. 

Selon notre conception, aucun de ces inhibiteurs ne doit affecter I amination du c toglutarate dans les tissue. Par contre, I amination du pyruvate et de I oxalac tate, si elle s op re par voie de transr imi-nation, sera d prim e par I inhibition de chacune des reactions du cycle situ es sur la route de conversion de ces composes en acide c to-glutarique. L amination sera susceptible d etre r6stitu par supplementation du systfeme avec du cetoglutarate ou tels de ses pr cur-seurs dont la trane ormation ne sera pas bloquee. 

---