Dainippon-Sumitomo Pharma Co., Ltd., 3-1-98 Kasugade-naka, Konohana-ku, 554-0022 Osaka, Japan.
J Physiol Biochem. 2011 Jun;67(2):259-64. doi: 10.1007/s13105-010-0071-1. Epub 2011 Jan 8.
Acyl-coenzyme A:diacylglycerol acyltransferase (DGAT) enzyme plays a significant role in dietary triacylglycerol (TAG) absorption in the small intestine. However, the characteristics of human intestinal DGAT enzyme have not been examined in detail. The aim of our study was to characterize the human intestinal DGAT enzyme by examining acyl-CoA specificity, temperature dependency, and selectivity for 1,2-diacylglycerol (DAG) or 1,3-DAG. We detected DGAT activity of human intestinal microsome and found that the acyl-CoA specificity and temperature dependency of intestinal DGAT coincided with those of recombinant human DGAT1. To elucidate the selectivity of human intestinal DGAT to 1,2-DAG or 1,3-DAG, we conducted acyl-coenzyme A:monoacylglycerol acyltransferase assays using 1- or 2-monoacylglycerol (MAG) as substrates. When 2-MAG was used as acyl acceptor, both 1,2-DAG and TAG were generated; however, when 1-MAG was used, 1,3-DAG was predominantly observed and little TAG was detected. These findings suggest that human small intestinal DGAT, which is mainly encoded by DGAT1, utilizes 1,2-DAG as the substrate to form TAG. This study will contribute to understand the lipid absorption profile in the small intestine.
酰基辅酶 A：二酰基甘油酰基转移酶 (DGAT) 酶在小肠中对膳食三酰基甘油 (TAG) 的吸收起着重要作用。然而，尚未详细研究人类肠道 DGAT 酶的特性。我们的研究旨在通过检查酰基辅酶 A 的特异性、温度依赖性以及对 1,2-二酰基甘油 (DAG) 或 1,3-DAG 的选择性来表征人肠道 DGAT 酶。我们检测了人肠道微粒体的 DGAT 活性，发现肠道 DGAT 的酰基辅酶 A 特异性和温度依赖性与人重组 DGAT1 一致。为了阐明人肠道 DGAT 对 1,2-DAG 或 1,3-DAG 的选择性，我们使用 1-或 2-单酰基甘油 (MAG) 作为底物进行酰基辅酶 A：单酰基甘油酰基转移酶测定。当 2-MAG 用作酰基受体时，会生成 1,2-DAG 和 TAG；然而，当使用 1-MAG 时，主要观察到 1,3-DAG，并且检测到很少的 TAG。这些发现表明，主要由 DGAT1 编码的人小肠 DGAT 利用 1,2-DAG 作为底物形成 TAG。本研究将有助于了解小肠中的脂质吸收情况。
