Competitive deposition of trans-12 and cis-9-octadecenoates into egg yolk lipids.

The deposition of trans-12-octadencenoate-12(13)-3H (12t-18:1-3H) was compared to cis-9-octadecenoate-10-14C (9c-18:1-14C) in the major egg yolk neutral lipids and phospholipids trans-12-Octadecenoate was preferentially incorporated into cholesteryl esters (CE), phosphatidylcholines (PC), and phosphatidylethanolamines (PE) but was discriminated against in triglycerides (TG). Isotopic ratios indicate that 5.9 and 5.6 times more 12t-18:1-3H than 9c-18:1-14C was esterified at the 1-acyl position of PE and PC, respectively. The combined 1- and 3-acyl positions of TG and the 2-acyl position of TG, PE and PC were each preferentially esterified with 9c-18:1-14C.