Schwartz H H, Reinauer H
Z Ernahrungswiss. 1979 Sep;18(3):149-59. doi: 10.1007/BF02020597.
The major maltase activity was found in the kidneys, followed by liver, muscle and blood. Only low maltase activity has been found in adipose tissue, muscle, and brain. The pH-optimum of kidney maltase was at pH = 6.0, the Michaelis-Menten Constant was measured to be 15.6 X 10(-3) mol/l. Even with a dose of 200 mg maltose/100 g body weight saturation of the hydrolysing system could not be attained in living rats. In nephrectomized rats the maltose oxidation was reduced to 55%. Only 0.2% of the applied maltose is excreted into the bile. According to our results the following main pathway of metabolism of maltose is suggested: glomerular filtration of maltose, hydrolysis of maltose to glucose by maltases which are localized in the membrane of the kidney brush borders, absorption of glucose, oxidation of glucose to CO2. In addition an extrarenal maltase activity is considered in the liver. The metabolism of injected trehalose was only 10% when compared with the metabolism of maltose.
主要的麦芽糖酶活性在肾脏中被发现，其次是肝脏、肌肉和血液。在脂肪组织、肌肉和大脑中仅发现低水平的麦芽糖酶活性。肾脏麦芽糖酶的最适pH值为pH = 6.0，测得米氏常数为15.6×10⁻³mol/L。即使给予200mg麦芽糖/100g体重的剂量，在活体大鼠中也无法使水解系统达到饱和。在肾切除的大鼠中，麦芽糖氧化减少至55%。仅0.2%的摄入麦芽糖排泄到胆汁中。根据我们的结果，提出了以下麦芽糖代谢的主要途径：麦芽糖的肾小球滤过，位于肾刷状缘膜上的麦芽糖酶将麦芽糖水解为葡萄糖，葡萄糖的吸收，葡萄糖氧化为二氧化碳。此外，肝脏中存在肾外麦芽糖酶活性。与麦芽糖的代谢相比，注射海藻糖的代谢仅为10%。
