Modelling carbohydrate transport through membranes

Modelling carbohydrate transport through membranes

Comp. Biochem. Physiol., 1968, Vol. 24, pp. 679 to 694. Pergamon Press. Printed in Great Britain NEWS ITEM Journal of Evolutionary Biochemistry and P...

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Comp. Biochem. Physiol., 1968, Vol. 24, pp. 679 to 694. Pergamon Press. Printed in Great Britain

NEWS ITEM Journal of Evolutionary Biochemistry and Physiology, Vol. 2, Nos. 2, 3 and 4 Printed in Russian (Leningrad) with English summaries

Lipid a n d Upoproteid membrane models: By G. A. DEBORIN and V. Z. BARANOVA: Institute of Biochemistry of the A c a d e m y of Sciences of the U S S R , Moscow, pp. 90-95. CURRENTviews on composition and structure of biological membranes are discussed. The results of investigations on models are reviewed, particularly concerning protein-lipid and lipoproteid films on different interfaces. An attempt has been made to correlate these observations to processes, responsible for control of enzymatic activity.

Modelling carbohydrate transport through membranes: By A. G. PASYNSKY and L. N. MOISF,EVA: Institute of Biochemistry of the Academy of Sciences of the U S S R , Moscow, pp. 96-101. A MODELof active carbohydrate transport through artificial polymer membranes has been studied in an open system involving two basic factors; (a) an enzymatic reaction transforming the compound supplied from the environment to a ionic form (glucose to glucose phosphate); (b) negative charges present on the membrane preventing reverse diffusion of the ionic produce of the reaction (glucose phosphate). Selective accumulation of glucose is shown to amount to 35-40 per cent of total diffusion transport over a polyacryl membrane having selectivity of 2, while glucose concentration over a sulpho-carboxyl membrane with selectivity amounting to 8 proved to be twice as high as in the medium. Densities of polymer membrane surface charges were measured by the electro-osmosis method. Membrane permeability for ionized compounds is shown to decrease with increasing density of surface charges.

Physical properties of phospholipid membrane models as influenced by e l e c t r i c a l field: By A. V. BABAKOV, L. N. ERMISHKIN and E. A. LmERM~'~: Institute of Biological Physics of the A c a d e m y of Sciences of the U S S R and Physico-Technical Institute, Moscow, pp. 102-108. CoMPt~SSmmia~ under the effect of electrical field has been studied on bi-molecular phospholipid models of cellular membranes. These membranes have been found to display marked and reversible augmentation of capacity on application of direct or alternating field of 0.1 V range. The augmentation of capacity has been shown by an optical method to depend on migration of the thicker parts 679