Crystal Clear collaboration

Crystal Clear Collaboration (see authors of Ref. [381). Figure 9.13 illustrates results from their work as summarized in the Status Report of this group of 3 September 1993. It will be interc.sting to see how this picture evolves in the coming years. 

The search for the C, compound formed by condensation of pyruvic and oxaloacetic acids, originally postulated by Krebs, had been fruitless for more than 10 years. In 1949 Ochoa with the collaboration of Joseph Stern isolated an enzyme from heart muscle capable of synthesizing stoichiometric amounts of citric acid from ATP, acetate, CoA and oxaloacetate. First named condensing enzyme , it is now known as citrate synthetase. It was obtained by the Ochoa group in crystalline form, the first enzyme of the cycle to be crystallized. With the pure enzyme in hand, it was clear not only that the product was not a C, compound, but that other alternatives to citrate, namely, m-aconitate and isocitrate, could also be rejected. The citrate synthetase condensation takes place between the methyl group of acetyl-CoA and the keto group of oxaloacetic acid the reaction is reversible. 

The horse liver alcohol dehydrogenase, crystallized by my collaborators Bonnichsen and Wassen in 1948, has been subject to much work the last 20 years, both in my lab and others. Its amino acid sequence (374 residues per subunit = molecule) was cleared up by my young collaborator Hans Jornvall working with I. J. Harris in Cambridge from 1967 and then with us in Stockholm. Alcohol dehydrogenases from other sources were also studied in our and many other peoples laboratories. It is at present one of the most intensively studied enzymes in the world. 

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