Nyomba B L, Mott D M
Clinical Diabetes and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona 85016.
J Clin Endocrinol Metab. 1994 Aug;79(2):485-8. doi: 10.1210/jcem.79.2.8045967.
In rabbit muscle, analyzed by Western blot, the glycogen-bound protein phosphatase-1 (PP-1G) is composed of a 37-kilodalton (kDa) catalytic subunit complexed to a 160-kDa glycogen-binding subunit (G-subunit) responsible for the interaction of PP-1G with glycogen. PP-1G has not been characterized in humans. In the present study, G-subunit was identified in human muscle extracts by Western blot using an antibody raised against a sequence (the phosphoregulatory domain) of the rabbit muscle G-subunit. The human G-subunit was also a 160-kDa protein by Western blot. When the G-subunit content of skeletal muscle was quantitated in 17 Pima Indians with a wide range of insulin sensitivities determined during euglycemic clamps, there was a significant negative correlation (r = -0.55; P = 0.02) between the G-subunit content and in vivo insulin-mediated glucose disposal rates. The results suggest that insulin resistance is associated with an increased content and/or immunoreactivity of G-subunit in human muscle.
在兔肌肉中，通过蛋白质印迹法分析发现，与糖原结合的蛋白磷酸酶-1（PP-1G）由一个37千道尔顿（kDa）的催化亚基和一个160 kDa的糖原结合亚基（G亚基）组成，该G亚基负责PP-1G与糖原的相互作用。PP-1G在人类中尚未得到充分表征。在本研究中，使用针对兔肌肉G亚基序列（磷酸调节结构域）产生的抗体，通过蛋白质印迹法在人类肌肉提取物中鉴定出了G亚基。通过蛋白质印迹法检测，人类G亚基也是一种160 kDa的蛋白质。在17名皮马印第安人中，在正常血糖钳夹期间测定了广泛的胰岛素敏感性，对骨骼肌中的G亚基含量进行定量时，发现G亚基含量与体内胰岛素介导的葡萄糖处置率之间存在显著负相关（r = -0.55；P = 0.02）。结果表明，胰岛素抵抗与人类肌肉中G亚基含量增加和/或免疫反应性增加有关。
