The invention relates to processes for performing biochemical reactions, such as in an aqueous in vitro reaction system. The processes involve macromolecules, particularly polypeptides, comprising one or more functional intrinsically disordered regions (IDRs). The invention also relates to IDR-macromolecules, including IDR-polypeptides, including macromolecules or polypeptides comprising a tagged amino acid sequence which comprises or consists of one or more functional IDRs. Such functional IDRs are capable of increasing the efficiency of the biochemical reaction. The invention relates to kits comprising any such macromolecules and polypeptides. The invention further relates to processes for stimulating or enhancing liquid-liquid demixing in a solution using any such macromolecules and polypeptides, including in combination with multivalent metal ions, thereby providing reagents capable of increasing the efficiency of a biochemical reaction.