Purificação e caracterização bioquímica de um inibidor tipo Bowman-Birk de sementes Luetzelburgia auriculata (Allemão) Ducke

Abstract

Plant protease inhibitors are proteins of low molecular weight, usually present in high concentrations in storage tissues, particularly in seeds of species belong to the Fabaceae family. In this study, a Bowman-Birk protease inhibitor (LzaBBI) was purified from the saline extract of the Luetzelburgia auriculata seeds After boiling of this saline extract, the inhibitor was purified by affinity chromatography on Sepharose® 4B-anhydrotrypsin, followed by ion exchange chromatography on DEAE Sepharose and reverse phase chromatography. Under reducing conditions or not, LzaBBI showed an apparent molecular mass of 17.3 kDa and a single polypeptide chain. The NH2-terminal sequencing of the LzaBBI showed high similarity with other Bowman-Birk inhibitors of legumes. LzaBBI remained stable after boiling at 98 °C for 120 min and also remained stable with trypsin inhibitory activity after incubation in pH buffers with pHs varying from 2 to 11. In addition to its relevant structural stability, of importance in future biotechnological applications, LzaBBI showed negative impact on the Staphylococcus aureus development when at low doses.