Cyp2b19 is a cytochrome P450 enzyme with arachidonic acid monooxygenase activity. It is highly expressed in the outer, differentiated cell layers of mouse epidermis and is a specific cellular marker of late differentiation in skin keratinocytes. It is involved in arachidonic acid metabolism, generating epoxyeicosatrienoic acids (EETs) and hydroxyeicosatetraenoic acids (HETEs), which are implicated in regulating epidermal cornification [1,2].

Research on primary cultures of mouse epidermal keratinocytes showed that differentiation upregulated Cyp2b19 mRNA levels, immunoreactivity, and the cellular levels of its product 11,12-EET [1]. Recombinant Cyp2b19 metabolizes arachidonic acid to generate EETs and HETEs in a stereoselective manner, and the EETs produced are endogenous constituents of murine epidermis, suggesting it might be the primary source of these EETs [2]. Also, in a study on type 2 diabetes mellitus-induced gastroenteropathy in db/db mice, Cyp2b19 was identified as one of the major proteins associated with T2DM-induced gastrointestinal injury, indicating its possible role in this disease-related process [3].

In conclusion, Cyp2b19 plays a crucial role in epidermal cornification through its involvement in arachidonic acid metabolism to produce EETs. Its association with T2DM-induced gastrointestinal injury also implies its potential significance in diabetes-related gastrointestinal pathophysiology. Mouse models, such as the db/db mice, have been valuable in uncovering these functions and disease-related associations of Cyp2b19.