Basically all chemical reaction is expressed as the reaction of reactant/s to form product/s. The main point with biochemical reaction is that the reaction is usually assisted by enzymes.
Enzymes are large biological molecules which are responsible for biological processes in living organisms. Enzymes catalyze the reaction in order to convert the substrates (biological term for reactants) into products.
The chemical reaction for biological reaction can be written as:
Substrate/s + Enzyme -> Enzyme-Substrate complex -> Products + Enzyme
Note that enzymes are biological catalysts which are not consumed or converted in the reaction. Regarding the balancing of the biological reaction, it is similar with general chemical reaction where the moles of the substrate and products are numbered. Enzymes are removed in the reaction or placed above the reaction arrow since they are both present in the reactants and products side.