NCIt definition : An aminoacyltransferase that catalyzes the second step in the ubiquitination reaction
via the transfer of activated ubiquitin from an E1 ubiquitin-activating enzyme to
itself via transthioesterification.;
NCIt note : The IUBMB has recategorized E2 ubiquitin-conjugating enzymes as transferases (EC 2);
specifically aminoacyltransferases (EC 2.3.2.-). There are 3 categories of E2 enzymes:
E3-dependent (EC 2.3.2.23), E3-independent (EC 2.3.2.24) and N-terminal E2 Ubiquitin-Conjugating
enzymes (EC 2.3.2.25) (2015);