Enzymatic characterization of recombinant α-amylase in the Drosophila melanogaster species subgroup: is there an effect of specialization on digestive enzyme?
We performed a comparative study on the enzymological features of purified recombinant α-amylase of three species belonging to the Drosophila melanogaster species subgroup: D. melanogaster, D. erecta and D. sechellia. D. erecta and D. sechellia are specialist species, with host plant Pandanus candelabrum (Pandanaceae) and Morinda citrifolia (Rubiaceae), respectively. The temperature optima were around 57-60℃ for the three species. The pH optima were 7.2 for D. melanogaster, 8.2 for D. erecta and 8.5 for D. sechellia. The kcat and Km were also estimated for each species with different substrates. The specialist species D. erecta and D. sechellia display a higher affinity for starch than D. melanogaster. α-Amylase activity is higher on starch than on glycogen in all species. α-Amylases of D. erecta and D. sechellia have a higher activity on maltooligosaccharides (G6 and G7) than on starch, contrary to D. melanogaster. Such differences in the enzymological features between the species might reflect adaptation to different ecological niches and feeding habits.
UPR 9034 Evolution, Génomes et Spéciation, CNRS, F-91198 Gif-sur-Yvette, France and Université Paris-Sud.
Céline
C
Commin
Magali
M
Aumont-Nicaise
Gaëlle
G
Claisse
Georges
G
Feller
Jean-Luc
JL
Da Lage
D000220:Adaptation, Biological; D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000145:classification / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D009844:Oligosaccharides / Q000378:metabolism; D010802:Phylogeny; D011994:Recombinant Proteins / Q000378:metabolism; D013045:Species Specificity; D013213:Starch / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D000516:alpha-Amylases / Q000378:metabolism*
D029721:Drosophila Proteins; D009844:Oligosaccharides; D011994:Recombinant Proteins; C021705:maltooligosaccharides; D013213:Starch; D000516:alpha-Amylases