Search

Aspergillus flavus isolated from fermented millet flour produced a crude enzyme, which was purified via ammonium sulphate precipitation and subsequent chromatographic techniques. The biochemical characteristics of the purified amylase were thereafter investigated showing activity in a wide range of pH and temperature, with optimal conditions of pH 6.0 and 50 °C. The enzyme retained even 89% of its activity after 1 h at 50 °C and 2 h at pH 6.0. The purified enzyme was stimulated by Ca2+, Zn2+ and Co2+, while Hg2+ and EDTA caused mild inhibition of a-amylase activity. The kinetic indices (Km and Vmax) and molecular weight of the enzyme were estimated in 1.71 mg mL-1, 2.133 µmol min-1 mL-1 and 45 kDa respectively. The catalytic properties of a-amylase from A. flavus makes it a promising candidate for use in various starch processing industries. [ABSTRACT FROM AUTHOR]

Copyright of MedULA is the property of Facultad de Medicina, Universidad de los Andes, Venezuela and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Physalis peruviana is an Andean specie whose fruits are eaten as food and also has been reported in Colombian folk medicine for diabetes mellitus treatment. In addition, previous pharmacological studies on diabetic Wistar rats, an extract of P. peruviana fruits has been showed antidiabetic activity. In order to deepen in P. peruviana action mode as antidiabetic, in this investigation were determinate the Inhibitory Concentrations 50 (IC50) of P. peruviana fruits crude extract on alpha glucosidase from S. cerevisiae and from intestinal rat powder, on maltase and alpha amylase enzymes. The kinetic behavior of the extract on each enzyme was also investigated, and the enzyme constant (Km) and maximum rate (Vmax) were determined. Extract of fruits of P. peruviana showed different IC50 for alpha glucosidase from S. cerevisiae and intestinal rat powder, suggesting greater affinity for the enzyme of mammalian source (4114.7 and 3552.7 μg/mL, respectively). For maltase, the IC50 was close to that obtained for alpha glucosidase (4191.0 μg/mL) while for alpha amylase, the extract exhibited the highest inhibition (IC50: 619.9 g/mL). Regarding kinetic behavior, the extract showed competitive inhibition on alpha-glucosidase and maltase, and on the non-competitive type of alpha amylase. These suggest that inhibition of intestinal carbohydrases is one of the modes of action for the antidiabetic activity of fruits of P. peruviana. [ABSTRACT FROM AUTHOR]