Le Chevalier P, Van Wormhoudt A
Institut Universitaire de Technologie, Quimper, France.
J Exp Zool. 1998 Apr 15;280(6):384-94.
Penaeus vannamei is an omnivorous species, and it can be assumed that a high level of carbohydrates is necessary for growth. Alpha-glucosidases are important enzymes necessary for the ultimate liberation of glucose residues from various carbohydrates. Using acarbose affinity chromatography, a glycosylated alpha-glucosidase with a molecular mass of approximately 105 kDa was isolated for the first time from the hepatopancreas of the shrimp. Exhibiting an optimal catalytic activity in the temperature range from 40 degrees C to 50 degrees C at pH 6, the purified enzyme hydrolyses alpha 1-4 bonds and liberates glucose from different oligo and polysaccharides. By contrast to other known glucosidases, no alpha 1-6 glucose link with hydrolysis has been observed. This could explain the different rates of growth in shrimp aquaculture with starches from various origins. The amino-acid composition, together with the partial sequence of a hydrolytic peptide, shows a high degree of similarity to the alpha-glucosidases reported for various organisms including yeast and fungi and may help determine the phylogeny of the family.
凡纳滨对虾是一种杂食性物种，可以认为高水平的碳水化合物对其生长是必需的。α-葡萄糖苷酶是将各种碳水化合物中的葡萄糖残基最终释放出来所必需的重要酶。利用阿卡波糖亲和色谱法，首次从虾的肝胰腺中分离出一种分子量约为105 kDa的糖基化α-葡萄糖苷酶。纯化后的酶在pH 6、温度范围为40℃至50℃时表现出最佳催化活性，可水解α-1,4键并从不同的寡糖和多糖中释放葡萄糖。与其他已知的葡萄糖苷酶不同，未观察到其对α-1,6葡萄糖键的水解作用。这可以解释不同来源淀粉在对虾养殖中生长速率的差异。该酶的氨基酸组成以及水解肽的部分序列与包括酵母和真菌在内的各种生物体中报道的α-葡萄糖苷酶具有高度相似性，可能有助于确定该家族的系统发育。
