Question

Often,

Answer 1

Cofactors

Explanation:

Enzymes are biochemicals which catalyze a biochemical reaction taking place in the body by reducing the activation energy barriers and changing the substrate molecules to products.  

The active sites of enzymes first binds to the substrate and forms an enzyme-substrate complex.

An enzyme can work actively only with the help of helper molecules called co-factors and co-enzymes.  

Co-factors are non-protein inorganic ions like iron, magnesium which helps the catalyze chemical reactions.  

Cofactors are bound tightly with the active sites of the enzymes and also contribute for the structural integrity and stability of the enzyme