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M O L EC U LA R B IO LO C Y

O F P L A N T

C E L L S IN VITRO

PROTEIN SYNTHESIS IN CALLUS AND SUSPENSION CELLS FROM

DIFFRENT14C-SUBSTRATES

L.P.Belova, T.M.Ilyna

Kazan Institute ofBiologi, Russian Academy o fScience, Kazan, 420503, Box 30

Metabolism of the radioactive carbon from bicarbonate or labelled protein

hydrolysate or labelled alanine in proteins of different (separated in solubility)

fractions and also proteins with different compartmentations- cytoplasm or

cell wall have been studied. The experiments were carried out on young,

intensively growing callus tissue and mixotrophic suspension culture soya

(the phase of exponential growth). Alkaline soluble proteins and sytoplasm

proteins from other labelled compounds have been separated by precipitating

TCA acid (to final concentration 7%). W ith the same purpose for water-

saltsoluble proteins and sytoplasm fractions dialysis was carred out using

dialysic pipes not passing molecules larger than 6-8 kD. Proteins from cell

wall were extracted by 3 M LiCI in 10 mM sodium-phosphate-citric buffer at

4 °C during 48 hours.

The same utilization of radioactive carbon from exgenous amino asids

and bicarbonate for biosynthesis proteins of separate fractions having different

compartmentation in the cell - cell wall and cytoplasm have been discovered.

A fte r 40-minutes exposure of cells with labelled substrates a relative

more incorporation of 14Cfrom bicarbonate in the water-salt soluble proteins

and cytoplasm proteins have been marked in comparison with the variant

where exogenous labelled amino acids were used as substrate. The latter

were preferably used in biosynthesis of cell wall proteins. The degree of

difference of rates renovation of cytoplasm proteins and cell wall proteins

was not the same in this two variants - more considerable exceeding of

specific radioactivity of cytoplasm proteins in comparison with that o f cell

wall proteins in variant with 14c-bicarbonate compared with the second variant

- with the 14c-protein hydrolysate.

The nature o f the regularities revealed is discussed in frames o f the

hypothesis tha t the space isolated fund or subfund o f amino acids having

close metabolic bond with transport stream of amino acids from outside

take part in protein synthesis o f cell wall.

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