The microsomes are re-formed vesicle-like artifacts, not ordinarily present in living cells, from pieces of the endoplasmic reticulum (ER), plasma membrane, mitochondria, and Golgi apparatus of broken eukaryotic cells. Typically, microsomes are separated by differential centrifuged from homogenized of cell or tissue. Based on enrichment of ER fractions, prepared microsomes mainly show a large of metabolic activity following high amount of metabolic enzyme, as cytochrome P450 (CYP). CYPs are important components of xenobiotic-metabolizing monooxygenase accounting for an approximate 75% of biotransformation of clinically relevant drugs. Hepatic CYP are ER-anchored hemoproteins involved in the metabolism of numerous endo- and xenobiotics including drugs, steroids, and carcinogens. The CYPs catalytic activity is subject to regulation via phosphorylation. In several previous studies, 8 CYP phosphorylation sites had been discovered in human. Protein kinase A (PKA) and protein kinase C (PKC) were identified as a major catalyst for the phosphorylation of CYPs in 2003. The phosphorylation of CYPs process to their ubiquitination undergoing ubiquitin-dependent 26S proteosomal degradation.