大麦β-淀粉酶同工酶的电泳特性研究

ELECTROPHORETIC CHARACTERIZATION OF BARLEY β-AMYLASE ISOZYME

大麦成熟籽粒中β-淀粉酶同工酶在聚丙烯酰胺凝胶电泳中至多能分辨4～5条酶带,而在薄层等电聚焦电泳中,能分辨20～30条酶带.用3种提取液提取的大麦成熟籽粒β-淀粉酶同工酶在薄层等电聚焦电泳中显示不同的酶活性和酶带数.用水提取的游离形β-淀粉酶活性最低,而用0.1 mol/L 巯基乙醇提取的同工酶活性明显提高,酶带加粗,但两者的电泳模式不变.用木瓜蛋白酶溶液提取的同工酶,不仅酶活性提高,而且同工酶的电泳模式也发生了改变,酶带移向碱性端,单体酶之间并发生聚合.3种提取液提取的β-淀粉酶加样于阳极端电泳与加样于阴极端电泳具有不同的酶带活性.用水和巯基乙醇提取的β-淀粉酶,加样于阳极端电泳后,酶活性大大地降低,而用木瓜蛋白酶提取的β-淀粉酶同工酶活性不受影响,这可能是由于木瓜蛋白酶促使小分子β-淀粉酶相互聚合后,酶的稳定性增加之故.

Only 4～5 bands of β-amylase isozyme in barley mature grains could be separated bygeneral polyacrylamide gel electrophoresis,but 30 β-amylase isozyme bands could be sepa-rated by thin-layer isoelectric focusing.Barley β-amylases isozyme extracted by three methods had different activity andelectrophoretic patterns.The activity of β-amylases isozyme extracted with water was thesmallest.The activity of β-amylases isozyme extracted with mercaptoethanol was largerthan that of β-amylases extracted with water,but the electrophoretic pattern did notchange.The β-amylase isozyme extracted with papain solution not only enhanced greatlythe enzymic activity but also changed the electrophoretic pattern.The activity of β-amylases isozyme extracted with water and mercaptoethanol set tothe anode was obviously different from that set to the cathode on electrophoresis,but theβ-amylase isozymcs extracted with papain set to both the anode and the cathode had thesame activity.That might be due to the fact that papain promotes polymerization ofβ-amylase monomers and increases enzymic stability.