Insights into scorpion venom peptides: Alternative processing of β-KTx propeptide from Tityus serrulatus venom results in a new naturally occurring thimet oligopeptidase inhibitor

► New pentapeptide KEILG from Tityus serrulatus venom is a EP24.15 inhibitor. ► A selective tool to differentiate EP 24.15 from EP24.16. ► Substitution of one residue affects the mechanism of inhibition. ► The sequence is homologue to the propeptide portion of βKTx. ► The presence of KEILG suggests a new processing of propeptides.