Koyama Iwao, Komine Shin-Ichi, Hokari Shigeru, Matsunaga Toshiyuki, Nakamura Koh-Ich, Komoda Tsugikazu
Department of Medical Technology, Junior College, Saitama Medical School, Japan.
Electrophoresis. 2002 Sep;23(19):3278-83. doi: 10.1002/1522-2683(200210)23:19<3278::AID-ELPS3278>3.0.CO;2-7.
Liver amylase activity in rodents was assayed with Blue Starch as substrate, and found to be higher than in humans or pigs. Based on the result of concanavalin A affinity chromatography, we found that the sugar moieties of amylase molecules increased in parallel with amylase activity in the tested mammals. However, the amounts of amylase proteins determined by Western bloting with anti-human salivary-type antibody as the probe, were similar to the levels in mammalian livers. Moreover, a similar expression of amylase mRNA was also detected in the mammalian livers by a reverse transcriptional-polymerase chain reaction using primers specific for the human salivary and/or pancreatic amylase complementary DNA (cDNA) sequences. The amylase was detected at the catalytic activity, protein molecule and mRNA levels in rat liver at all ages from fetus to adult. Salivary-type liver amylase activity increased up to one week after birth, and was maintained at the adult level thereafter. However, based on the results of the electrophoretic mobility test, livers with accelerated amylase activity, e.g., at 2-4 weeks after birth or during liver regeneration after partial hepatectomy, were also found to express an amylase electrophoretical identical to pancreatic-type amylase in addition to salivary-type activity. These results suggest that the liver may express an etopic amylase in a certain condition.
以蓝色淀粉为底物测定了啮齿动物肝脏中的淀粉酶活性，发现其高于人类或猪。基于伴刀豆球蛋白A亲和层析的结果，我们发现受试哺乳动物中淀粉酶分子的糖基部分与淀粉酶活性呈平行增加。然而，以抗人唾液型抗体为探针通过蛋白质印迹法测定的淀粉酶蛋白量，与哺乳动物肝脏中的水平相似。此外，使用针对人唾液和/或胰腺淀粉酶互补DNA（cDNA）序列的引物，通过逆转录-聚合酶链反应在哺乳动物肝脏中也检测到了相似的淀粉酶mRNA表达。从胎儿到成年的所有年龄段大鼠肝脏中，均在催化活性、蛋白质分子和mRNA水平检测到淀粉酶。唾液型肝脏淀粉酶活性在出生后一周内升高，此后维持在成年水平。然而，根据电泳迁移率测试结果，发现淀粉酶活性加速的肝脏，如出生后2-4周或部分肝切除术后肝脏再生期间，除了唾液型活性外，还表达一种电泳上与胰腺型淀粉酶相同的淀粉酶。这些结果表明，肝脏可能在某些条件下表达异位淀粉酶。
