An ensymic method for the preparation of millimole quantities of d(−)-β-hydroxybutyrate

✍ Scribed by B.J. Passingham; R.N. Barton

• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 240 KB
• Volume: 65
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(75)90527-8

✦ Synopsis

A method is described for preparing the physiologically active isomer D(-)-phydroxybutyrate in quantities of several millimoles by the reduction of acetoacetate, catalysed by /3-hydroxybutyrate dehydrogenase at pH 8. Economy in the use of coenzyme is achieved by coupling the reaction to the oxidation of galactose, catalysed by D-galactose dehydrogenase. The progress of the reaction can be followed by decarboxylating the remaining acetoacetate with aniline citrate, trapping the evolved CO2 in Ba(OH), and back titrating with HCI. After incubation for 48 h at 35" the mixture is acidified and continuously extracted with ether for 13 h. The ether extract is evaporated to dryness and the residue is dissolved in water and neutralized to give a solution of sodium o(-)-P-hydroxybutyrate.

In a typical preparation the final yield determined enzymically agreed with that determined by optical rotation and titration, and specific tests showed that the product was free of the following contaminants: acetoacetate. D(t)-galactose, phosphate and o(-)-galactono-y-lactone.