Aromatase

Isoform of cytochrome P-450 Aromatase is an enzyme that converts androgens to estrogens . Human aromatase is a protein consisting of a sequence of 503 amino acid residues ^[2] . The N-terminal portion of the molecule, especially amino acid residues 10-20, are important for maintaining the active conformation of the enzyme, since if the cleavage of the first 10 amino acids does not affect aromatase activity, then the cleavage of 20 amino acids already leads to a decrease in its activity by more than 95% ^{[3 ]} . Near the C-terminus of the molecule there is a heme-binding site (containing an important cysteine ​​residue that remains in the phylogenetic row).

An example of the relationship between tumor development and the level of signaling molecules regulated by the expression of cytochrome P-450 isoforms is breast cancer in women. A limiting step in the synthesis of estradiol in breast cells is the dehydrogenation of testosterone , catalyzed by aromatase ^[4] . It has been shown that aromatase expression during menopause is not uniform across breast cells. A direct correlation was revealed between the increased mRNA level and aromatase enzymatic activity in certain areas of the mammary gland and, consequently, a local chronic increase in estrogen levels in these areas with the development of a tumor in them ^{[5] [6]} .