5–Aminolevulunic Acid (5-ALA)
5-ALA – Naturally occurring amino acid
5-ALA stands for 5-aminolevulinic acid, a type of amino acid which is produced universally by life forms such as plants and animals. In the human body, 5-ALA is a component of a substance called heme which is formed by a combination of eight 5-ALA molecules and is key to a number of vital functions.
A familiar function of heme is the formation of red pigment (hemoglobin) in the blood, which distributes oxygen throughout the body. Oxygen and heme combine or separate, depending on the surrounding environment, and oxygen is delivered from the lungs throughout the entire body. In addition, heme is the central substance in the respiratory chain complex that produces energy from food and oxygen, which is the basis of our vital functions. Without 5-ALA we would not be able to gain energy or even move.
Chlorophyll, which plays a central role in plant photosynthesis, is also formed by combining eight 5-ALA molecules, and its structure is very close to heme. Plants produce oxygen and cells by photosynthesis using light and carbon dioxide. Animals, including humans, consume oxygen and plants and exhale carbon dioxide and plants grow again using that same carbon dioxide. This is the energy cycle of life and it cannot be achieved without its two axes—heme and chlorophyll— both of which are formed from 5-ALA.
5-ALA – Ingestion
In many cases, simply ingesting a substance that originally exists in the body will not reach its place of origin or the place where its effects are needed. However, this isn’t the case for 5-ALA, as oral ingestion allows it to exert its original function AND change into heme.
This is possible because firstly, 5-ALA is created in mitochondria, tiny organs (organelles) inside the cell, but is then immediately expelled from the mitochondria. After being assembled almost into its final form outside the mitochondria, it is then reintroduced into the mitochondria before bonding with iron (iron atoms) to complete the heme production (see diagram).
Secondly it is due to the size of 5-ALA. In general, water-soluble substances like 5-ALA cannot pass through cells, but 5-ALA’s structure and size is similar to dipeptide, a two-amino-acid chain produced during the breakdown of protein (food) and can pass through cells using a gate (called a transporter) for dipeptides on the cell surface.
Therefore orally ingested 5-ALA and 5-ALA naturally produced in the body are combined inside the cell/outside the mitochondria and together form heme.
5-ALA – Accumulation of Protoporphyrin IX (PpIX)
The synthesis of 5-ALA is regulated by an intracellular pool of free heme through a negative feedback mechanism. Administration of an excess of exogenous 5-ALA bypasses the negative feedback control, resulting in selective accumulation of protoporhyrin IX (PpIX) in tumor cells such as malignant gliomas or actinic keratoses.
