There are very few enzymes as determinant as Stearoyl-CoA desaturase, commonly know as SDC (EC 126.96.36.199), for cellular physiology.
SCD catalyzes the rate-limiting step in the production of Mono-Unsaturated Fatty Acids (MUFA), that are major components of tissue lipids. SCD is the only mammalian enzyme that can insert the first double bond in a saturated carbon chain. Among the fatty acids synthetized by SCD , the Palmitoleic Acid (16:1n7), the Oleic Acid (18:1n9) and the vaccenic Acid (18:1n7) are certainly the most important and most common ones.
Therefore, SCD is the only enzyme capable of synthetizing MUFA and granting a certain level of double bonds and fluidity inside membranes, since Poly-Unsaturated Fatty Acids (PUFA) cannot be synthetized in mammals. SCD is also involved in the regulation of inflammation and stress in various cell types.
SCD is bound to the endoplasmic reticulum (ER), with N and C termini and the catalytic site being orientated toward the cytosolic side of the membrane. Interestingly, its half-life is only of 3-5 hours; therefore, it seems that normal cellular function requires the expression of SCD to be tightly controlled.
For those of you who would like to know more about SCD, we suggest three reviews describing its activity and regulation in detail: Hodson & Fielding, 2013; Liu et al., 2011; Miyazaki & Ntambi, 2003.
If you are interested in evaluating its expression, activity and influence on cell metabolism, we suggest you an analysis of the fatty acid composition of the membrane network of cells or tissues you use for your research studies. This would definitely bring great added value to your research.