Complex sentence: The idea of enzyme adaptation was thus replaced with the concept of enzyme induction, in which a molecule induces expression of a gene or operon, often by binding to a repressor protein and preventing it from attaching to the operator.
Split into simpler sentences: The idea of enzyme adaptation was thus replaced with the concept of enzyme induction. A molecule induces expression of a gene or operon by binding to a repressor protein and preventing the repressor from attaching to the operator.