Cofactors, such as NAD(H) and NADP(H), are carriers for biosynthetic reactions, catabolic reactions and act as important energy transferring agents of energy. They can be considered as "helper molecules" that assist in biochemical transformations. Cofactors are subclassified as either inorganic ions, such as metal ions and iron-sulfur clusters, or complex organic molecules called coenzymes, such as vitamins and derivatives and non-vitamins.

Since the importance of cofactors for a biocatalysis reaction, it is necessary to select the most suitable natural cofactor or a combination of, or even artificial, synthetic cofactors. Sometimes a change of the cofactor is necessary due to the change of the substrate. For example, glucose isomerase is a microbial enzyme with Mn²⁺ acting as essential cofactor for substrate xylose. But Co²⁺ is more efficient for the reaction when glucose is converted to the more valuable fructose. On the other hand, manipulation in use of cofactors is critical in metabolic engineering. In this process, commonly known as cofactor engineering, the concentrations of cofactors are changed in order to maximize or minimize metabolic fluxes. It can be used to optimize the production of a metabolite product or to increase the efficiency of a metabolic network.

Creative Enzymes provides potential cofactors suitable for biocatalysis reactions. The process is based on library screening or rational design. We also perform cofactor engineering for optimization of metabolic pathways. Our unique advantages make cofactor selection and modification easier and every before and cover a wide range of research subjects:

• Reaction medium optimization.
• Cofactor library screen.
• Synthetic cofactor design.
• Cofactor engineering strategies.

Figure 1. Cofactors provide redox carriers for biosynthetic reactions, catabolic reactions
(Current Opinion in Biotechnology, 2013)