Elongase

This pathway (the microsomal system ) elongates saturated and unsaturated fatty acyl-CoAs (from Cjg upward) by two carbons, using malonyl-CoA as acetyl donor and NADPH as reductant, and is catalyzed by the microsomal fatty acid elongase system of enzymes (Figure 21-5). Elongation of stearyl-CoA in brain increases rapidly during myehnation in order to provide C22 and C24 fatty acids for sphingoEpids. 

Figure 21-S. Microsomal elongase system for fatty acid chain elongation. NADH is also used by the reductases, but NADPH is preferred.

SYNTHESIS OF POLYUNSATURATED FATTY ACIDS INVOLVES DESATURASE ELONGASE ENZYME SYSTEMS... 

Figure 23-3. Biosynthesis of the co9, co6,and co3 families of polyunsaturated fatty acids. Each step is catalyzed by the microsomal chain elongation or desaturase system 1,elongase 2,A desaturase 3,A desaturase 4,A desaturase. ( .Inhibition.)...

Biosynthesis of unsatutated long-chain fatty acids is achieved by desaturase and elongase enzymes, which introduce double bonds and lengthen existing acyl chains, respectively. 

Fig. 3.3.1 Pathways of essential fatty acid formation from the dietary (poly)unsaturated fatty acids. The total set of elongases and desaturases has not been completely clarified. The notation (n-3) and (n-6) are alternatives for ( -3) and (co-6), respectively...

Increasing the degree of unsaturation and chain length of these fatty acids is achieved by enzymes known as desaturases and elongases (Sinnhuber et al., 1972). Their activity is greatly influenced by temperature, as we have seen earlier under temperature compensation , even in isolated systems. Schiinke and Wodtke (1983) observed a 30-fold increase in the desaturase activity of the... 

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