Many enzymes require the involvement of an additional, non-protein component in order to carry out their catalytic action. These 'extra' parts are called cofactors; they
Activation energy without enzyme Activation energy with enzyme
Change in free energy (aG)
Figure 6.4 An enzyme lowers the activation energy of a reaction. By lowering the amount of energy that must be expended in order for a reaction to commence, enzymes enable it to proceed much more quickly. Note that AG, the change in free energy, remains the same whether the reaction is catalysed or not are usually either metal ions (e.g. Mg2+, Zn2+) or complex organic molecules called coenzymes. Some of the most important coenzymes act by transferring electrons between substrate and product in redox reactions (see below).
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Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...