Secreted fungal aspartic proteases: a review / Aspartil-proteasas secretadas por hongos: revisión

The aspartic proteases, also called aspartyl and aspartate proteases or acid proteases (E.C.3.4.23), belong to the endopeptidase family and are characterized by the conserved sequence Asp-Gly-Thr at the active site. These enzymes are found in a wide variety of microorganisms in which they perform important functions related to nutrition and pathogenesis. In addition, their high activity and stability at acid pH make them attractive for industrial application in the food industry; specifically, they are used as milk-coagulating agents in cheese production or serve to improve the taste of some foods. This review presents an analysis of the characteristics and properties of secreted microbial aspartic proteases and their potential for commercial application (AU)

Las aspartil-proteasas, también denominadas aspartato-proteasas o proteasas ácidas (E.C.3.4.23), pertenecen a la familia de las endopeptidasas, que se caracterizan por una secuencia conservada de Asp-Gly-Thr en su sitio activo. Estas enzimas se encuentran distribuidas en una amplia variedad de microorganismos, donde desempeñan funciones importantes en la nutrición y la patogenia, además de poseer otras características, como alta actividad catalítica y estabilidad en pH ácido, lo que las vuelve atractivas para su uso en industrias como la alimentaria, específicamente en la industria láctea, como agentes coagulantes para la elaboración de quesos o para mejorar el sabor de ciertos alimentos. En la presente revisión se lleva a cabo un análisis de las características y propiedades de las aspartil-proteasas secretadas por hongos y su potencial para aplicaciones comerciales (AU)

Secreted fungal aspartic proteases: A review.

The aspartic proteases, also called aspartyl and aspartate proteases or acid proteases (E.C.3.4.23), belong to the endopeptidase family and are characterized by the conserved sequence Asp-Gly-Thr at the active site. These enzymes are found in a wide variety of microorganisms in which they perform important functions related to nutrition and pathogenesis. In addition, their high activity and stability at acid pH make them attractive for industrial application in the food industry; specifically, they are used as milk-coagulating agents in cheese production or serve to improve the taste of some foods. This review presents an analysis of the characteristics and properties of secreted microbial aspartic proteases and their potential for commercial application.

Purification and characterization of the extracellular aspartyl protease APSm1 from the phytopathogen fungus Stenocarpella maydis.

The extracellular protease APSm1 was purified to homogeneity from Stenocarpella maydis that was grown in acidic minimal media with glucose and ammonium sulfate. The purification procedure consisted of ion exchange chromatography coupled to an FPLC (Fast Protein Liquid Chromatography) system, resulting in a 15.3% recovery and a 2.3-fold increase in specific activity. The molecular weight of the purified enzyme was estimated to be 56.8 kDa by SDS-PAGE. Enzymatic activity toward hemoglobin was optimal at pH 2.0 and at 25 °C. The effects of six protease inhibitors on APSm1 activity were tested. Pepstatin A inhibited APSm1 activity, as the protein is in fact an aspartyl protease. The pure enzyme degraded hemoglobin, albumin and proteins obtained from corn germ at pH 3 but did not have any milk-clotting activities. The Km and Vmax values obtained were 0.514 mg/mL and 0.222 µmol/min, respectively, using hemoglobin as the substrate. This work is the first to report the purification of a secreted aspartyl protease from S. maydis.

Biochemical study of the extracellular aspartyl protease Eap1 from the phytopathogen fungus Sporisorium reilianum.

In this work, the extracellular protease Eap1 from Sporisorium reilianum was characterized in solid and liquid cultures using different culture media. The results showed that Eap1 was produced in all media and under all culture conditions, with the most activity in solid culture at an acidic pH of 3-5. Following purification, the 41 kDa protease demonstrated aspartyl protease activity. The enzyme was stable at a wide range of temperatures and pH values, but 45°C and pH 3 were optimal. The K(m) and V(max( values obtained were 0.69 mg/mL and 0.66 µmol/min, respectively, with albumin as the substrate. Eap1 degraded hemoglobin as well as proteins obtained from corn germ, roots, stems and slides at pH 3 and also had milk-clotting activity. Sequencing analysis showed that this protein has 100% similarity to the peptide sequence theoretically obtained from the sr11394 gene, which encodes an aspartyl protease secreted by S. reilianum.