Fysiologiskt inaktiva ämnen som kan omvandlas till aktiva enzymer.
Protein precursors, also known as proproteins or preproproteins, are inactive forms of proteins that undergo post-translational modification to become active. These precursors contain additional sequences of amino acids, called signal peptides, which direct the protein to specific cellular compartments for processing. During processing, enzymes remove the signal peptide and may cleave the protein into smaller functional units. The resulting mature protein can then perform its intended function in the body.