Self-association of phosphorylase kinase from rabbit skeletal muscle in the presence of natural osmolyte, trimethylamine N-oxide

Interaction of Hsp27 with Native Phosphorylase Kinase under Crowding Conditions

“…Molecular crowding noticeably influences interactions between macromolecules as well as the rate and equilibrium of intracellular biochemical processes 14–17, 24, 25. Analyzing the effect of crowding on phosphorylase b (Ph b ) and PhK, we found that crowding affects many important reactions of key enzymes of glycogenolysis such as association, conformational transitions, interaction with allosteric ligands, denaturation, and aggregation 10, 12, 13, 18–20, 24. Many effects of crowding seem to be a result of protein association and aggregation.…”

“…The PhK with molecular mass of 1 320 kDa4 has a complex molecular organization and consists of four subunits that form a hexadecamer (αβγδ) 4 , where the γ‐subunit possesses the catalytic activity and α‐, β‐, and δ‐subunits regulate its activity 4–7. Ca 2+ and Mg 2+ stimulate the PhK activity by inducing changes in the tertiary and quaternary structure of the molecule5–9 and also stimulate hexadecamer association 10–13…”

Biochemical effects of molecular crowding

“…The influence of TMAO on the self association of phosphorylase kinase from rabbit skeletal muscle has been studied by sedimentation velocity and turbidimetry [80]. It was shown that TMAO (0.6 1.0 M) stimulates the association of phosphorylase kinase induced by Ca 2+ and Mg 2+ .…”

Effect of molecular crowding on self‐association of phosphorylase kinase and its interaction with phosphorylase b and glycogen

“…Ca 2þ and Mg 2þ ions stimulate the PhK activity by inducing tertiary and subsequent quaternary structural changes in the enzyme molecule (Nadeaw et al, 1999;Wilkinson et al, 1999). In the absence of Ca 2þ and Mg 2þ , the enzyme exists in the monomeric and dimeric forms with s 20;w ¼ 23 S (that corresponds to a molecular mass of 1320 kDa) and s 20;w ¼ 36:5 S, respectively (Cohen, 1973;Chebotareva et al, 2002). However, the addition of 0.1 mM Ca 2þ and 10 mM Mg 2þ results in the appearance of higher-order associates (Carlson and King, 1982;Chebotareva et al, 2002).…”

“…In the absence of Ca 2þ and Mg 2þ , the enzyme exists in the monomeric and dimeric forms with s 20;w ¼ 23 S (that corresponds to a molecular mass of 1320 kDa) and s 20;w ¼ 36:5 S, respectively (Cohen, 1973;Chebotareva et al, 2002). However, the addition of 0.1 mM Ca 2þ and 10 mM Mg 2þ results in the appearance of higher-order associates (Carlson and King, 1982;Chebotareva et al, 2002). In skeletal muscle about 40% of phosphorylase kinase is localized, together with Phb and other enzymes of glycogen metabolism, on the surface of glycogen granules (Meyer et al, 1970), and is really functioning as a part of the protein-glycogen complex.…”