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Developmental pattern in the formation of various multienzyme complexes associated with Benson-Calvin cycle in cotton leaves

Babadzhanova, M. A., Mirzorakhimov, A. K., Babadzhanova, M. P., Esanalieva, Sh. A.
Russian journal of plant physiology 2010 v.57 no.2 pp. 175-180
Gossypium hirsutum, adenosine triphosphate, cotton, epigenetics, flowering, leaves, multienzyme complexes, phosphates, ribose, ribulose-bisphosphate carboxylase
An electrophoretically homogeneous preparation of a multienzyme complex with a mol wt of 520 ± 20 kD was isolated from 15- to 25-day-old cotton (Gossypium hirsutum L.) leaves uniform in their age and position on the shoot (3rd to 4th leaves from the top when the plants possessed 5-6 true leaves). When cotton leaves were sampled at the stage of budding and flowering, two complexes with mol wts of 520 ± 20 kD and 480 ± 15 kD were isolated. Comparative enzymatic studies of these complexes revealed developmental changes in activities of ribose phosphate isomerase, phosphoribulokinase, and ribulose-bisphosphate carboxylase. The multienzyme complexes were almost identical in activity of ribose phosphate isomerase. Activities of phosphoribulokinase and ribulose-bisphosphate carboxylase for various multienzyme complexes showed variations between 14 and 17% in the presence of ribose-5-phospate + ATP as a substrate, but the differences were smaller (6-7%) in the presence of specific substrates of these enzymes. The formation of multienzyme Benson-Calvin cycle complexes, featuring different properties at various stages of plant development, is presumably related to the increased demand in assimilates for epigenetic processes during formation of generative organs.