title: Alternative method for quantification of alfa-amylase activity.
abstract: A modification of the sensitive agar diffusion method was developed for macro-scale determination of alfa-amylase. The proposed modifications lower costs with the utilisation of starch as substrate and agar as supporting medium. Thus, a standard curve was built using alfa-amylase solution from Aspergillus oryzae, with concentrations ranging from 2.4 to 7,500 U.mL-1. Clear radial diffusion zones were measured after 4 hours of incubation at 20 A degrees C. A linear relationship between the logarithm of enzyme activities and the area of clear zones was obtained. The method was validated by testing alpha-amylase from barley at the concentrations of 2.4; 60; 300 and 1,500 U.mL-1. The proposed method turned out to be simpler, faster, less expensive and able to determine on a macro-scale alpha-amylase over a wide range (2.4 to 7,500 U.mL-1) in scientific investigation as well as in teaching laboratory activities.
authors.affiliation: Departamento de Biologia, Universidade Federal do Ceará, Fortaleza, CE, Brazil.
authors.forename: D F
authors.initials: DF
authors.lastname: Farias
authors.forename: A F U
authors.initials: AF
authors.lastname: Carvalho
authors.forename: C C
authors.initials: CC
authors.lastname: Oliveira
authors.forename: N M
authors.initials: NM
authors.lastname: Sousa
authors.forename: L C B
authors.initials: LC
authors.lastname: Rocha-Bezerrra
authors.forename: P M P
authors.initials: PM
authors.lastname: Ferreira
authors.forename: G P G
authors.initials: GP
authors.lastname: Lima
authors.forename: D C
authors.initials: DC
authors.lastname: Hissa
mesh_terms: D000362:Agar; D001236:Aspergillus oryzae / Q000201:enzymology*; D002623:Chemistry Techniques, Analytical / Q000191:economics / Q000379:methods*; D004058:Diffusion; D015203:Reproducibility of Results; D000516:alpha-Amylases / Q000032:analysis*
chemical_list: D000362:Agar; D000516:alpha-Amylases