What Are Coenzymes?
Coenzymes, sometimes called cosubstrates, are organic nonprotein cofactors that assist enzymes in driving chemical reactions in the body. Although they are not enzymes themselves, coenzymes are small molecules that temporarily attach to inactive enzymes, known as apoenzymes. It’s important to note that not all enzymes need these cofactors to perform their functions.
Think of the relationship between coenzymes and enzymes as similar to a lock and key mechanism. The apoenzyme is like the lock, and the coenzyme acts as the key. Only specific keys (coenzymes) can fit into certain locks, the active sites on apoenzymes. This unique fit ensures that only the correct coenzymes will work effectively.
How Coenzymes Function
Coenzymes are able to detach themselves from the enzyme after a biochemical reaction has occurred due to their temporary binding with the apoenzymes. This allows them to participate in additional enzymatic reactions. Another type of cofactors, known as prosthetic groups, operate similarly but are usually metal ions that bind much more tightly to the apoenzymes via covalent bonds. Unlike coenzymes, prosthetic groups cannot easily detach.
When a cofactor, be it a coenzyme or prosthetic group, binds with an apoenzyme, they form a complex known as a holoenzyme, which is the enzyme’s active form. Beyond facilitating enzyme function, coenzymes also help transfer compounds between different enzymes, incrementally altering the original molecule along the enzymatic pathway.
Coenzymes play a pivotal role in ensuring that the correct compounds are brought to and the incorrect compounds are kept away from an enzyme’s active site. This is particularly crucial due to the phenomenon of competitive inhibition, where the wrong compound binds to an enzyme’s active site and prevents it from functioning properly. This mechanism regulates enzyme activity when it’s not needed.
Why Are Coenzymes Essential?
Ever wondered why certain conditions arise from vitamin deficiencies? One reason is that some vitamins are converted into coenzymes. Without these vitamins, some enzymes can’t perform their tasks correctly, or at all. This highlights why certain vitamin forms are better than others and why some are described as metabolically inactive.
Coenzymes are integral for the transfer of functional groups, electrons, hydrogens, and energy within the body. Some even enhance the stability or reactivity of an enzyme’s product. For example:
| Coenzyme | Enzyme | Vitamin Precursor | Function |
|---|---|---|---|
| Methylcobalamin (B-12) | Methionine synthase and others | B-12 | Transfers the methyl group |
| NAD (Nicotinamide adenine dinucleotide) | Malate Dehydrogenase, pyruvate dehydrogenase and others | B6 | Transfers electrons and hydrogen atoms |
| FAD (Flavin adenine dinucleotide) | D-lactate dehydrogenase and others | B2 | Transfers electrons and hydrogen atoms |
| Coenzyme Q (ubiquinone) | Cytochrome c – oxidoreductase and others | B5 | Transfers electrons and hydrogen atoms |
| Biotin | Propionyl-CoA carboxylase and others | Biotin | Carries carboxyl groups |
How to Support Proper Enzymatic Function
When you’re not well-nourished, your cells can’t produce the necessary products or carry out essential processes needed to maintain good health. Many diseases and conditions can stem from nutritional deficiencies. Coenzymes work on a molecular level, but their impact is felt throughout the entire body. Therefore, it’s crucial to consume the proper, active forms of these vitamins, which are naturally present in whole, plant-based foods. Examples of healthy vegan sources include peanuts, tree nuts, and beans.
An exception to this is vitamin B12, which has many inactive forms that are not useful for enzymes. To ensure you get the correct form of vitamin B12, look for methylcobalamin on the label. This particular coenzyme aids in detoxifying excess homocysteine in your tissues by converting it into methionine, an essential amino acid. Adenosylcobalamin is another vital form of B12 that is essential for protein and fat metabolism. Due to the importance of these forms of B12 for vascular, brain, and metabolic health, we created our own Vitamin B12 supplement. This certified organic liquid contains methylcobalamin, adenosylcobalamin, and also hydroxocobalamin for prolonged support, with 5,000 mcg of B12 per serving.
