title: Molecular, Biochemical, and Dietary Regulation Features of α-Amylase in a Carnivorous Crustacean, the Spiny Lobster Panulirus argus.
abstract: Alpha-amylases are ubiquitously distributed throughout microbials, plants and animals. It is widely accepted that omnivorous crustaceans have higher α-amylase activity and number of isoforms than carnivorous, but contradictory results have been obtained in some species, and carnivorous crustaceans have been less studied. In addition, the physiological meaning of α-amylase polymorphism in crustaceans is not well understood. In this work we studied α-amylase in a carnivorous lobster at the gene, transcript, and protein levels. It was showed that α-amylase isoenzyme composition (i.e., phenotype) in lobster determines carbohydrate digestion efficiency. Most frequent α-amylase phenotype has the lowest digestion efficiency, suggesting this is a favoured trait. We revealed that gene and intron loss have occurred in lobster α-amylase, thus lobsters express a single 1830 bp cDNA encoding a highly conserved protein with 513 amino acids. This protein gives rise to two isoenzymes in some individuals by glycosylation but not by limited proteolysis. Only the glycosylated isoenzyme could be purified by chromatography, with biochemical features similar to other animal amylases. High carbohydrate content in diet down-regulates α-amylase gene expression in lobster. However, high α-amylase activity occurs in lobster gastric juice irrespective of diet and was proposed to function as an early sensor of the carbohydrate content of diet to regulate further gene expression. We concluded that gene/isoenzyme simplicity, post-translational modifications and low Km, coupled with a tight regulation of gene expression, have arose during evolution of α-amylase in the carnivorous lobster to control excessive carbohydrate digestion in the presence of an active α-amylase.
authors.affiliation: Center for Marine Research, University of Havana, Havana, Cuba.|Department of Biology, University of Cadiz, Puerto Real, Cadiz, Spain.
authors.forename: Leandro
authors.initials: L
authors.lastname: Rodríguez-Viera
authors.affiliation: Instituto de Ciencias Marinas de Andalucía, ICMAN-CSIC, Puerto Real, Cadiz, Spain.
authors.forename: Erick
authors.initials: E
authors.lastname: Perera
authors.affiliation: Instituto de Ciencias Marinas de Andalucía, ICMAN-CSIC, Puerto Real, Cadiz, Spain.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Martos-Sitcha
authors.affiliation: Department of Biochemistry, Center for Pharmaceuticals Research and Development, Havana, Cuba.
authors.forename: Rolando
authors.initials: R
authors.lastname: Perdomo-Morales
authors.affiliation: Center for Marine Research, University of Havana, Havana, Cuba.
authors.forename: Antonio
authors.initials: A
authors.lastname: Casuso
authors.affiliation: Department of Biochemistry, Center for Pharmaceuticals Research and Development, Havana, Cuba.
authors.forename: Vivian
authors.initials: V
authors.lastname: Montero-Alejo
authors.affiliation: Center for Marine Research, University of Havana, Havana, Cuba.
authors.forename: Tsai
authors.initials: T
authors.lastname: García-Galano
authors.affiliation: Instituto de Ciencias Marinas de Andalucía, ICMAN-CSIC, Puerto Real, Cadiz, Spain.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Martínez-Rodríguez
authors.affiliation: Department of Biology, University of Cadiz, Puerto Real, Cadiz, Spain.
authors.forename: Juan Miguel
authors.initials: JM
authors.lastname: Mancera
mesh_terms: D000818:Animals; D060829:Arthropod Proteins / Q000096:biosynthesis / Q000235:genetics; D060435:Carnivory / Q000502:physiology*; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D006031:Glycosylation; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics; D033521:Palinuridae / Q000235:genetics / Q000378:metabolism; D059748:Proteolysis; D000516:alpha-Amylases / Q000096:biosynthesis / Q000235:genetics
chemical_list: D060829:Arthropod Proteins; D018076:DNA, Complementary; D007527:Isoenzymes; D000516:alpha-Amylases