Development of aqueous two-phase systems-based approaches for the selective recovery of metalloproteases and phospholipases A toxins from Crotalus molossus nigrescens venom.

Snake venoms are rich sources of proteins with potential biotechnological and pharmaceutical applications. Among them, metalloproteases (MPs) and phospholipases A2 (PLA) are the most abundant. Their isolation involves a multistep chromatographic approach, which has proven to be effective, however implies high operating costs and long processing times. In this study, a cost-effective and simple method based on aqueous two-phase systems (ATPS) was developed to recover MPs and PLA from Crotalus molossus nigrescens venom. A system with PEG 400 g mol, volume ratio (V) 1, tie line length (TLL) 25% w/w and pH 7 showed the best performance for PLA recovery. In systems with PEG 400 g mol, V 1, TLL 15% w/w, pH 7 and 1 and 3% w/w of NaCl, selective recovery of MP subtype P-III was achieved; whereas, in a system with PEG 400 g mol, V 1, TLL 25% w/w and pH 8.5, MP subtypes P-I and P-III were recovered. Due to their low costs, ethanol-salt systems were also evaluated, however, failed to differentially partition PLA and MPs. The use of ATPS could contribute to the simplification and cost reduction of protein isolation processes from snake venoms and other toxin fluids, as well as potentially aid their biochemical, proteomic and biological analyses.