Comparison of catabolic rates of C-13-labeled palmitic acid bound to the alpha and beta positions of triacylglycerol using CO2 expired from mice

作者：Beppu Fumiaki; Konno Kaoru; Kawamatsu Takashi; Nagai Toshiharu; Yoshinaga Kazuaki; Mizobe Hoyo; Kojima Koichi; Watanabe Hiroyuki; Gotoh Naohiro^*

来源：European Journal of Lipid Science and Technology, 2015, 117(5): 718-723.

DOI：10.1002/ejlt.201400326

• C-13-labeled carbon dioxide
• Binding position
• Catabolism
• Fatty acid
• Triacylglycerol

We investigated the catabolic rate of C-13-labeled palmitic acid (*P) bound to alpha (sn-1) or beta (sn-2) position of triacylglycerol (TAG) using isotope-ratio mass spectrometry. Specifically, we measured the C-13-to-C-12 ratio in CO2 expired from mice. After 30-75 min, *P bound to the alpha position was catabolized faster than that bound to the beta position. Thereafter, the catabolic rate of *P bound to the beta position increased and surpassed that bound to the alpha position. This indicated that binding position affected the catabolic rate of *P, possibly due to the different specificities of pancreatic lipase, lipoprotein lipase, and hepatic lipase. Next, we measured the catabolic rate of *P bound to TAG in combination with one of three unsaturated fatty acids (oleic acid, linoleic acid, or alpha-linolenic acid). When *P was bound to the beta position and Ln was bound to the alpha position, the catabolism of TAG was significantly higher than for other TAGs. This result suggests that fatty acid structure might affect the catabolism of counterpart fatty acids in TAG.

• 出版日期2015-5