E2, e2, E02, E.II, e² or E-2 may refer to: in biology or medicine: Ubiquitin-conjugating enzyme, a protein component of proteasome-mediated protein degradation E2 regulatory sequence for the insulin gene Prostaglandin E2 Prostaglandin E2 receptor, a human gene E02 : Subclinical iodine-deficiency hypothyroidism ICD-10 code Oestradiol (estradiol) Dihydrolipoyl transacetylase, the second element of the multienzyme pyruvate dehydrogenase complex in technology : E2 (cipher), a block cipher subm… (More on E2)