Wiktionary
preproinsulin
n. (context biochemistry English) A biologically inactive precursor to the endocrine hormone insulin.
Wikipedia
Preproinsulin
Preproinsulin is the primary translational product of the INS gene. It is a peptide that is 110 amino acids in length. Preproinsulin is a proinsulin molecule with a signal peptide attached to its N-terminus.