Acyl CoA:diacylgycerol acyltransferase (EC; DGAT) catalyzes the final step in 
the production of triacylglycerol. Two polypeptides, which co-purified with DGAT 
activity, were isolated from the lipid bodies of the oleaginous fungus 
Mortierella ramanniana with a procedure consisting of dye affinity, 
hydroxyapatite affinity, and heparin chromatography. The two enzymes had 
molecular masses of 36 and 36.5 kDa, as estimated by gel electrophoresis, and 
showed a broad activity maximum between pH 6 and 8. Based on partial peptide 
sequence information, polymerase chain reaction techniques were used to obtain 
full-length cDNA sequences encoding the purified proteins. Expression of the 
cDNAs in insect cells conferred high levels of DGAT activity on the membranes 
isolated from these cells. The two proteins share 54% homology with each other 
but are unrelated to the previously identified DGAT gene family (designated 
DGAT1), which is related to the acyl CoA:cholesterol acyltransferase gene 
family, or to any other gene family with ascribed function. This report 
identifies a new gene family, including members in fungi, plants and animals, 
which encode enzymes with DGAT function. To distinguish the two unrelated 
families we designate this new class DGAT2 and refer to the M. ramanniana genes 
as MrDGAT2A and MrDGAT2B.