Cytochrome P450, family 11, subfamily A, polypeptide 1 (P45011a1), often referred to as P450scc is a mitochondrial enzyme associated with the conversion of cholesterol to pregnenolone. The gene name is CYP11A1. The term "desmolase" is becoming outdated and the enzyme is now commonly referred to as P450scc, where "scc" refers to side chain cleavage. The protein is a member of the cytochrome family of enzymes. The protein resides on the inner mitochondrial membrane, facing the interior (matrix). The presence of this enzyme defines if a cell is steroidogenic. Consequently, P450scc is found in all steroid-producing cell types such as theca cells and luteal cells in the ovary, Leydig cells in the testis and cell types in the adrenal cortex.