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Phosphoglucomutase from a number of mammalian sources has been studied by electrophoresis. The phosphoglucomutase present in most tissues consists of a number of electrophoretically distinct enzymes.By column chromatography partial resolution of these isoenzymes can be achieved. They could not be distinguished catalytically. None appeared to be dephosphoenzyme. Addition of ^-mercuribenzoate or partial T Xo account for the polymorphism of phosphoglucomutase, three mechanisms may be proposed. The first of these was advanced by Najjar and Pullman (1954), who postulated a mechanism of enzyme action such that phosphorylated and dephosphorylated enzyme species must exist. It was subsequently shown that these

This study investigated effects of roasted or extruded oilseed supplementation ranging in n-6/n-3 ratios from 0.3 to 5.0 on the fatty acid composition and expression of delta-5 desaturase (D5d) and D6-desaturase (D6d) protein in commercial steer cheek (m. masseter) and diaphragm (pars costalis diaphragmatis) muscles. In general, the n-6/n-3 ratio of the diet had a subsequent effect on the muscle n-6/n-3 ratio (P , 0.05), with muscle 18:2n-6 and 18:3n-3 content relating to proportion of dietary soya bean and linseed (P , 0.01). Compared with canola, pure linseed and soya bean diets reduced 14:1c-9 and 16:1c-9 (P , 0.05) but increased 18:1t-11 and c-9,t-11 conjugated linoleic acid (CLA) content (P , 0.01). Oilseed processing had a minor influence but extruded oilseeds increase 18:1t-11 and c-9,t-11 CLA compared with roasted (P , 0.05). Polar lipid 18:3n-3 and n-3 long-chain polyunsaturated fatty acid (LC, >20 carbons PUFA) derivative content increased in relation to dietary linseed supplementation in the diaphragm (P , 0.01), whereas only 18:3n-3 was increased in the cheek (P , 0.01). Protein expression did not differ between diets; however, in each muscle the D5d protein expression had a stronger association with the desaturase products rather than the precursors. The relationship between D5d protein expression and the muscle LC n-6/n-3 ratio was negative in both muscles (P , 0.05). The relationship between D6d protein expression and the LC n-6/n-3 ratio was positive in the cheek (P , 0.001) and negative in the diaphragm (P , 0.05). In conclusion, diet n-6/n-3 ratio affected muscle 18:2n-6 and 18:3n-3 deposition, whereas the D5d and D6d protein expression had some influence on the polar lipid LC-PUFA profile. Results reaffirm that processed oilseeds can be used to increase the proportion of fatty acids potentially beneficial for human health, by influencing the formation of LC-PUFA and reducing the n-6/n-3 ratio.