Structure and enzyme properties of Zabrotes subfasciatus α‐amylase

Abstract

Digestive alpha-amylases play an essential role in insect carbohydrate metabolism. These enzymes belong to an endo-type group. They catalyse starch hydrolysis, and are involved in energy production. Larvae of Zabrotes subfasciatus, the Mexican bean weevil, are able to infest stored common beans Phaseolus vulgaris, causing severe crop losses in Latin America and Africa. Their alpha-amylase (ZSA) is a well-studied but not completely understood enzyme, having specific characteristics when compared to other insect alpha-amylases. This report provides more knowledge about its chemical nature, including a description of its optimum pH (6.0 to 7.0) and temperature (20-30 degrees C). Furthermore, ion effects on ZSA activity were also determined, showing that three divalent ions (Mn2+, Ca2+, and Ba2+) were able to enhance starch hydrolysis. Fe2+ appeared to decrease alpha-amylase activity by half. ZSA kinetic parameters were also determined and compared to other insect alpha-amylases. A three-dimensional model is proposed in order to indicate probable residues involved in catalysis (Asp204, Glu240, and Asp305) as well other important residues related to starch binding (His118, Ala206, Lys207, and His304).

Recognition and Binding of the PF2 Lectin to α-Amylase From Zabrotes subfasciatus (Coleoptera:Bruchidae) Larval Midgut

“…Detection with AntiAmy showed a band of ∼50 kDa ( Fig. 2 A), which coincides with the mass reported for Z. subfasciatus amylase ( Pelegrini et al. 2006 ).…”

Molecular and structural characterization of a trypsin highly expressed in larval stage of Zabrotes subfasciatus

“…Polyphagous insects, especially the post-harvest storage-pests, have the ability to synthesize in their digestive tracts several hydrolytic enzymes, which can process a wide range of dietary inputs (Terra and Ferreira, 1994;Franco et al, 2004;Pelegrini et al, 2006). Among them, the Mexican bean weevil, Zabrotes subfasciatus, is capable to attack cotyledons from common beans (Phaseolus vulgaris), cowpeas (Vigna unguiculata), and peas (Pisum sativum) (Silva et al, 2001a,b).…”

Major Digestive Enzymes of Butterfly of Eurema blanda and Catopsilia pomona

“…Butterflies are often in the open place to get sunlight and increase body temperature 17 . The cause of the decreased amylase activity after the optimum temperature is the denaturation of the hydrophobic residues, such as tryptophan and phenylalanine, on the enzyme surface which important for stabilize the amylase structure 18 . At the optimum pH, the charge of amino acid residuesare in an appropriate state, so the enzyme activity is efficient.…”