Fig. 1

Schematic diagram of multi-enzyme catalysis. A Ideal multi-enzyme catalytic system would inhibit negative external attack and promote the transfer of intermediates between adjacent enzymes. The design and construction of multienzyme catalytic systems often confront challenges, the intermediate product produced by the first step reaction, enzyme I may diffuse back to the overall environment, inhibit the intermediate enrichment around enzyme II and reduce the activity. The multi-enzyme catalytic systems may be degraded by protease, produce toxic substances, or encounter other external attacks. B Scheme of a compartmentalized cascade reaction, Compartmentalization for in vivo multi-enzyme reactions could inhibit the negative external attack toward multi-enzymes by encasing them in a robust and semi-permeable membrane. C Substrate channeling for in vivo multi-enzyme reactions could facilitate the transfer of intermediates between neighboring enzymes by shortening the inter-enzyme distance. D Simulation diagram of substrate channel effects in the catalytic process of cascading enzymes in metabolic compartments