Phosphoglucomutase activation

Kanazawa, K. and Ashida, H. (1991). Relationship between oxidative stress and hepatic phosphoglucomutase activity in rats. Int. J. Tissue React. 13, 225-231. 

B16. Bodansky, O., Phosphoglucomutase activity in human serum. Cancer 10, 859-864 (1957). 

Caspar, C, Huber. S. C., and Somerville, C. 1986. Alterations in growth, photosynthesis and respiration in a starch mutant of Arabidopsis thaliana (L.), Heynh deficient in chloroplast phosphoglucomutase activity. Plant Physiol. 79, 1-7. 

In three cases, a n-glucose-producing amylase was absent. In one case, muscle phosphoglucomutase activity was only 5% of normal, and subsequent glycolysis was 25% of normal. ... 

Spinach chloroplast envelope membranes, incubated in vitro in the presence of [y PJATP, incorporated labelled phosphate mainly in three proteins exhibiting Mr of 67, 26 and 14 kDa. Two of them, the 26 and 14 kDa phosphoproteins, are pools of LHCIIb and Rubisco small subunit tightly bound to envelope membranes [1] and are phosphorylated by a unique Ca -dependent serine protein kinase [2]. The 67 kDa phosphoprotein is likely to be autophosphorylated its P-labelling would take place via its own phosphoglucomutase activity [2-4]. The aim of this investigation is to modulate envelope protein kinase activities following incubation for various times with the phospholipase C (PLC) from Bacillus cereus or the lipase from Rhizopus arrhizus (LRa). 

The best replacement cation for Mg2+ on a size basis is Ni2+. However, Ni2+-substituted enzymes are usually inactive, with the exception of phosphoglucomutase. The failure of Ni2+ to activate these enzymes is usually attributed to the relative lack of lability of Ni11 complexes. In phosphoglucomutase the metal cation is bound to the leaving group and so the reluctance of Ni11 to vacate its site is of no significance. 

Phosphoglucomutase catalyzes the interconversion of glucose 1-phosphate and glucose 6-phosphate via a phosphoenzyme intermediate in which the phosphate is bound to a serine residue at the active site. The Mg2+ is not bound to the phosphate, but studies with the Nin-substituted enzyme suggest the presence of a second-sphere complex between phosphate and metal, which could ensure correct positioning of the phosphoryl group for nucleophilic attack, as shown in Figure 14.278... 

The conversion of D-mannose 6-phosphate into D-mannosyl phosphate is catalyzed by phosphomannomutase, an enzyme distinct from phosphoglucomutase. Both enzymes have been detected by Mathe-son705 in cassia seeds, mung beans, orchid tubers, and pea seedlings. These enzymes from cassia seeds have been separated from one another by chromatography on DEAE- and O-phosphono-cellulose columns, and further characterized. Phosphomannomutase from animal sources requires the presence of either D-galactose 1,6-bisphosphate or D-mannose 1,6-bisphosphate for activity.708 D-Mannosyl phosphate may then be enzymically transformed into GDP-D-mannose in the... 

Figure 15-3 Coupled enzyme assay to determine glycogen phosphorylase activity. As long as the activity of phosphoglucomutase and glucose-6-phosphate dehydrogenase are not rate-limiting, the AA340/At is directly proportional to the A[glucose-l -phosphate]/Atime.

Neuhaus, H. E and Stitt, M. 1990. Control analysis of photosynthate partitioning Impact of reduced activity of ADPglucose pyrophosphorylase or plastid phosphoglucomutase on the fluxes to starch and sucrose in Arabidopsis. Planta. 182,445-454. 

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