Growth and characterization of Cu2ZnSn(S,Se)(4) thin films for solar cells

status: publishe

Alternative method for quantification of alfa-amylase activity Alternativa para quantificação de alfa-amilase

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 °C. A linear relationship between the logarithm of enzyme activities and the area of clear zones was obtained. The method was validated by testing &#945;-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 &#945;-amylase over a wide range (2.4 to 7,500 U.mL-1) in scientific investigation as well as in teaching laboratory activities.<br>Modificações foram propostas ao método sensível de difusão em ágar para a macrodeterminação de alfa-amilase. As modificações propostas diminuem os custos, com a utilização de amido como substrato e ágar como meio solidificante. Assim, foi construída uma curva padrão utilizando uma solução de alfa-amilase de Aspergillus oryzae com concentrações variando de 2,4 a 7.500 U.mL-1. Em seguida, as zonas claras de difusão radial foram mensuradas depois de 4 horas de incubação a 20 °C. Foi obtida uma relação linear entre o logaritmo da atividade enzimática e os diâmetros das zonas claras. O método foi validado utilizando-se soluções de alfa-amilase de cevada nas concentrações de 2,4; 60; 300 e 1.500 U.mL-1. O método tornou-se mais simples, rápido, com baixo custo e passível de ser utilizado para macrodeterminação de alfa-amilase em ampla faixa (2,4 a 7.500 U.mL-1) na investigação científica e para fins didáticos em aulas práticas

Alternative method for quantification of alfa-amylase activity

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 °C. A linear relationship between the logarithm of enzyme activities and the area of clear zones was obtained. The method was validated by testing α-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 α-amylase over a wide range (2.4 to 7,500 U.mL-1) in scientific investigation as well as in teaching laboratory activities