Effects of calcium ion concentration on starch hydrolysis of barley α-amylase isozymes

Jeong-Bin Yuk, Seung-Ho Choi, Tae-Hee Lee, Myoung-Uoon Jang, Jung-Mi Park, Ah-Rum Yi, Birte Svensson, Tae-Jip Kim

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    Barley (x-amylase genes, amyl and amy2, were separately cloned into the expression vector of pPICZ alpha A and recombinant Pichia strains were established by homologous recombination. Both AMYs from Pichia shared almost identical hydrolysis patterns on short maltooligosaccharides to result in glucose, maltose, or maltotriose. Against insoluble blue starch, AMY1 showed the highest activity at 0.1-5 mM calcium concentration, whereas 15-20 mM was optimal for AMY2. On the hydrolysis of soluble starch, unexpectedly, there was no significant difference between AMYs with increase of calcium. However, the relative activity on various starch substrates was significantly different between AMYs, which supports that the isozymes are clearly distinguished from each other on the basis of their unique preferences for substrates.
    Original languageEnglish
    JournalJournal of Microbiology and Biotechnology
    Issue number4
    Pages (from-to)730-734
    Publication statusPublished - 2008


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