Coxentsyymien

Coxentsyymien are a proposed class of enzymes described in theoretical biochemistry as catalysts that couple the exchange of coenzymes with substrate turnover. In the conceptual framework, these enzymes would facilitate the direct shuttling of a coenzyme between distinct catalytic sites within a single polypeptide or protein complex, enabling rapid redox handoffs without diffusion-limited steps.

The name combines coenzyme and enzyme, reflecting the central role of coenzyme cofactors in their proposed mechanism. The term has appeared in theoretical discussions to address observations of rapid coenzyme cycling in some multienzyme assemblies, where traditional models struggle to explain the reported rates of turnover.

Structurally, models posit a modular arrangement with a catalytic core and a dedicated coenzyme-binding domain. In some proposals, a bound metal ion or a flavin cofactor participates in electron transfer, supporting a ping-pong or ordered sequential mechanism. The active site architecture would allow selective interaction with a specific coenzyme (for example, Coenzyme X) and with substrate.

Evidence to date is indirect. Experimental confirmation remains limited, with most support arising from computational analyses, synthetic constructs, or fragments that emulate aspects of the proposed exchange. Isolated examples from bacteria, archaea, or fungi under unusual conditions have been cited, but robust in vivo demonstration is lacking.

If validated, Coxentsyymien could reshape understanding of intracellular redox networks and enable new biocatalysis approaches, including streamlined coenzyme recycling and multi-step organic synthesis. See also: oxidoreductases, coenzymes, protein complexes, biocatalysis.