Sphingolipids are derived from the condensation of palmitoyl CoA and serine which forms sphingosine. Sphingolipids are constituents of neuronal tissue. Sphingolipids with containing carbohydrate components such as glucose and galactose, are called gangliosides. Page 689 Figure 27.6 Figure 27.7 Inherited genetic diseases effecting sphingolipid metabolism have been identified. A. Complete absence of this enzymes results in the accumulation of the ganglioside GM2 which builds up in the brain and causes death by the age of 5 years old.
Carriers contain one normal gene copy of hexoseaminidase A and one defective gene.
Genetic screening can be used to identify carriers and for testing fetuses in utero. There is no treatment currently available for Tay Sachs disease and it is considered a terminal illness. All 27 carbon atoms of cholesterol are derived from acetyl CoA. Squalene a C30 hydrocarbon is an intermediate in the cholesterol biosynthesis pathway. Radiosotope labeling experiments, and metabolic studies in bacteria, were used to elucidate the cholesterol biosynthetic pathway. 27.16 Bile salts are highly effective biological detergents that solubilize dietary lipids in the small intestine.