Izumoring: a strategy for bioproduction of all hexoses.

Izumoring is a new concept for the bioproduction of all hexose sugars - 16 aldohexoses, eight ketohexoses and 10 hexitols -- using enzymatic and microbiological reactions. The biocatalysts necessary for the strategy were (i) d-tagatose 3-epimerase [which epimerizes all ketohexoses at C-3 of the sugar], (ii) polyol dehydrogenases [which catalyze oxidation-reduction reactions between ketohexoses and the corresponding hexitols], and (iii) aldose isomerases [which catalyze isomerization reactions between aldohexoses and corresponding aldoketoses]. All ketohexoses, aldohexoses and hexitols may be arranged in a symmetric ring connected by the biochemical reactions, allowing the design for the bioproduction of all 34 hexose sugars. The ring shows there are four entrances to the l-hexose world from the natural d-hexoses. The Izumoring ring shows clearly the relationship and the position of all 34 six carbon sugars.

[Stereochemistry--an overlooked problem in medical treatment and research]. / Stereokemi--et overset problem i medicinsk behandling og forskning.

On the background of marketing of an increasing number of drug racemates with the subsequent problems for medical treatment and research, a short review is given focusing on the optic isomery and the significance of optic isomeric drugs for medical treatment and research. Different problems, which may arise in relation to the use of drug racemates are mentioned. The racemic problem is elucidated by examination of and reference to existing studies on drug racemates including studies on pharmacodynamic and pharmacokinetic properties of pure (+) and (-)enantiomers. As the receptor systems of the organism and the process of drug metabolization are stereoscelective, the ideal demand to drug racemates should be that they are regarded as two different drugs until investigations have clarified the degree of pharmacodynamic/pharmacokinetic differences between the (+) and (-)enantiomer. Whether the single enantiomer should be preferred to the racemate may be difficult to decide and may require considerable research, but solution of this can, on the other hand, give valuable advances in drug treatment, for instance in form of drugs with more selective and fewer side effects.