New action pattern of a maltose-forming alpha-amylase from Streptomyces sp. and its possible application in bakery.
New action pattern of a maltose-forming alpha-amylase from Streptomyces sp. and its possible application in bakery.
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DOI：
10.5483/bmbrep.2002.35.6.568
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发表时间：
2002-11
期刊：
影响因子：
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通讯作者：
Y. B. Ammar;Takayoshi Matsubara;Kazuo Ito;M. Iizuka;T. Limpaseni;P. Pongsawasdi;N. Minamiura
中科院分区：
文献类型：
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作者：
Y. B. Ammar;Takayoshi Matsubara;Kazuo Ito;M. Iizuka;T. Limpaseni;P. Pongsawasdi;N. Minamiura
纯化的α-淀粉酶（EC 3.2.1.1）可催化淀粉产生高水平的麦芽糖，而不产生葡萄糖。该酶是由嗜热链霉菌在细胞外产生的。这是与泰国土壤隔绝的。通过醇沉淀、DEAE-纤维素和凝胶过滤色谱法实现纯化。纯化的酶在pH 6-7和60℃下表现出最大活性。经SDS-PAGE测定，其相对分子质量为45 kDa。通过 1 H-NMR 测定，淀粉的水解产物具有 α-异头形式。这种形成麦芽糖的 α-淀粉酶完全水解可溶性淀粉，产生高含量的麦芽糖，含量高达 90%。它水解麦芽四糖和麦芽三糖，主要产生麦芽糖（分别为 82% 和 62%），而不产生葡萄糖。作为淀粉和麦芽低聚糖的最终产品的高麦芽糖水平，以及这种酶的独特作用模式，表明了一种不寻常的麦芽糖形成系统。在面包烘烤过程中添加酶后，面包的体积增大，并且比未添加酶的面包更长时间地保持其柔软度。
An a-Amylase (EC 3.2.1.1) was purified that catalyses the production of a high level of maltose from starch without the attendant production of glucose. The enzyme was produced extracellularly by thermophilic Streptomyces sp. that was isolated from Thailand's soil. Purification was achieved by alcohol precipitation, DEAE-Cellulose, and Gel filtration chromatographies. The purified enzyme exhibited maximum activity at pH 6-7 and 60 degrees C. It had a relative molecular mass of 45 kDa, as determined by SDS-PAGE. The hydrolysis products from starch had alpha-anomeric forms, as determined by 1H-NMR. This maltose-forming alpha-Amylase completely hydrolyzed the soluble starch to produce a high level of maltose, representing up to 90%. It hydrolyzed maltotetrose and maltotriose to primarily produce maltose (82% and 62% respectively) without the attendant production of glucose. The high maltose level as a final end-product from starch and maltooligosaccharides, and the unique action pattern of this enzyme, indicate an unusual maltose-forming system. After the addition of the enzyme in the bread-baking process, the bread's volume increased and kept its softness longer than when the bread had no enzyme.