Isolation and identification of a snake venom metalloproteinase inhibitor from California ground squirrel (Spermophilus beecheyi) blood sera

► We isolate a snake venom metalloproteinase inhibitor (SVMPI) from blood of Spermophilus beecheyi. ► This SVMPI had a molecular mass of 108.3 kDa and a pI of 5.1. ► The IC50 against whole venom from Crotalus oreganus was determined to be 3.14 × 10−8 M. ► Proteomic analysis showed homology to inter-α trypsin inhibitor, HP25 and HP27. ► Convergence on SVMP inhibition in different mammals suggests a key step in venom neutralization.