Influence of Osmolytes on Inactivation and Aggregation of Muscle Glycogen Phosphorylase b by Guanidine Hydrochloride. Stimulation of Protein Aggregation under Crowding Conditions

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T. B. Eronina^*, N. A. Chebotareva, and B. I. Kurganov

Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, 119071 Moscow, Russia; fax: (7-095) 954-2732; E-mail: eronina@inbi.ras.ru

^* To whom correspondence should be addressed.

Received October 14, 2004

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The effects of the osmolytes trimethylamine-N-oxide (TMAO), betaine, proline, and glycine on the kinetics of inactivation and aggregation of rabbit skeletal muscle glycogen phosphorylase b by guanidine hydrochloride (GuHCl) have been studied. It is shown that the osmolytes TMAO and betaine exhibit the highest protective efficacy against phosphorylase b inactivation. A test system for studying the effects of macromolecular crowding induced by osmolytes on aggregation of proteins is proposed. TMAO and glycine increase the rate of phosphorylase b aggregation induced by GuHCl.

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KEY WORDS: muscle glycogen phosphorylase b, guanidine hydrochloride, inactivation, aggregation, osmolyte

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