Snakebites cause upwards of 1.8 million envenomings, 138,000 deaths and 500,000 cases of long term morbidity each year. Viper
snake venoms (family Viperidae) generally contain a high proportion of
proteases which can cause devastating effects such as
hemorrhage, coagulopathy,
edema,
necrosis, and severe
pain, in envenomed victims. In this study, analytical techniques were combined with enzymatic assays to develop a novel method for the detection of
snake venom protease activity by using rhodamine-110-peptide substrate. In the so called at-line nanofractionation set up, crude
venoms were first separated with reversed phase liquid chromatography, after which fractions were collected onto 384-well plates.
Protease activity assays were then performed in the 384-well plates and bioassay chromatograms were constructed revealing
protease activity. Parallel obtained UV absorbance, MS and proteomics data from a previous study facilitated toxin identification. The application of the rhodamine-110-peptide substrate assay showed significantly greater sensitivity compared to prior assays using
casein-
FITC as the substrate. Moreover, cross referencing UV and MS data and resulted in the detection of a number of tentative
proteases suspected to exhibit
protease activity, including
snake venom serine proteases from Calloselasma rhodostoma and Daboia russelli
venom and a
snake venom metalloproteinase from the
venom of Echis ocellatus. Our data demonstrate that his methodology can be a useful tool for selectively identifying
snake venom proteases, and can be applied to provide a better understanding of
protease-induced pathologies and the development of novel
therapeutics for treating
snakebite.