Usmanov Ra

Charge transfer interactions in transketolase-thiamine pyrophosphate complex.

Abstract Absorption spectra of apo- and holotransketolase were measured and the results were compared with those of model systems. This comparison suggests that thiamine pyrophosphate, coenzyme of transketolase, interacts with tryptophanyl residue in the active centre of apoenzyme. The mechanism involved is supposed to be that of charge transfer complex formation.

The role of the charge transfer complex in the transketolase catalyzed reaction

Abstract Thiamine pyrophosphate (TPP), when bound with transketolase (TK) induces some changes in the absorption of the enzyme and coenzyme which can be registered by difference spectrophotometry. The binding of a donor substrate to the binary complex give rise to changes in the absorption region of the TPP thiazolium ring and in the charge transfer spectrum. With low concentrations of hydroxypyruvate, the kinetics of these changes may be revealed. The possibility is discussed of the charge transfer complex (CTC) being involved in the catalytic reaction.

A new method of determination of transketolase activity by asymmetric synthesis reaction.

Abstract A new method is proposed for assaying transketolase activity. The method is based on determining erythrulose, the product of the transketolase reaction, by its optical activity.