alpha-Glucosidase from the hepatopancreas of the shrimp, Penaeus vannamei (Crustacea-Decapoda).
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.
Le Chevalier
P
P
Institut Universitaire de Technologie, Quimper, France. chevalie@iutquimp.univ-brest.fr
Van Wormhoudt
A
A
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D004064:Digestive System / Q000201:enzymology*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D033561:Penaeidae / Q000201:enzymology*; D011817:Rabbits; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013816:Thermodynamics; D000520:alpha-Glucosidases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
D000596:Amino Acids; D000520:alpha-Glucosidases