Difference Between Arginine and L-Arginine

Arginine vs L-Arginine

Arginine is an α- amino acid commonly abbreviated as ‘Arg’ which was first isolated by a Swiss chemist named Ernst Schultze in 1886 from a lupin seedling extract. The significant presence of the element ‘N’ is a specialty in the chemical structure of Arginine and hence, is useful in the synthesis of proteins. Depending on the stereochemistry, the chemical structure of Arginine just like any other complex chemical structure can be oriented in different ways. Therefore, there are two recognizable types of these structures namely, D-Arginine and L-Arginine. Often D-Arginine is referred to as the inactive form of L-Arginine.

What is Arginine?

Like any other amino acid, Arginine too has four main parts in its chemical structure. The COO- group, the H atom, the NH2 group and the R group which is the side chain. The R group is made up of 3 Carbon aliphatic straight chain, and the end of the chain is capped with a guanidinium group which is centralized around the ‘N’ element. The guanidinium group remains positively charged in acidic, neutral and basic pH media and hence displays basic properties. The conjugation present within the guanidinium group and the COO- group offers lots of potential for chemistry.

The D and L labelling in stereo-chemical configuration is unrelated to being optically active with d/l (dextrorotatory/ levorotatory) labelling. It gives you information about the arrangement of the elements in a given structure and is helpful in identifying the active form of a compound. By following a simple rule called the ‘CORN’ rule, it is possible to identify which isomeric form a particular amino acid belongs to, from the D and L. While the groups, CO OH, R, NH2 and H are arranged around the chiral centre and when looking at the molecule from the opposite side of the H atom (facing the H atom, which will now be behind), if the arrangement of the CO-R-N groups are counter-clockwise, then it is said to be in the L form and, if the groups are arranged clockwise, it would be in the D form. Here, L-Arginine is the active form of the two and is commonly found in natural proteins.

What is L-Arginine?

L-Arginine is a conditionally nonessential amino acid included in the 20 most common amino acids, meaning that it is not required to depend on the diet in order to obtain it. However, most times, the biosynthetic pathways do not produce the required amount of L-Arginine hence the rest should be obtained from any dietary intake. Arginine is found in a variety of foods; dairy products (cheese, milk etc.), beef, pork, seafood, poultry, wheat flour, chickpeas, nuts, etc. L-Arginine is also commonly sold at pharmacies in supplement form when additional intake is prescribed medically. Just as much as it helps to produce protein, L-Arginine also helps to get rid of body ammonia, which is a waste product and increases the release of insulin. It also acts as a precursor for nitric oxide which helps in t he relaxation of blood vessels, making Arginine a life saver for people suffering from heart disease.

Therefore, in general, L-Arginine provides support to the body in wound healing, to maintain immune and hormone function and to help the kidneys remove waste products. However, any additional intake of Arginine should be done under medical inspection as an overdose can cause various side effects and can be very harmful.

What is the difference between Arginine and L-Arginine?

• Arginine is the common name given to the chemical structure of the respective compound whereas, L-Arginine is labelled for the identification of the proper stereochemistry of the active compound.

• Arginine is an α-amino acid, and its L form falls among the 20 most common amino acids needed for the production of natural proteins.

• While D-Arginine serves as the inactive form of L-Arginine and only assists for testing purposes to chemically replace L-Arginine, the latter has displayed many helpful effects towards the body and especially acts as a precursor to a powerful neurotransmitter, which aids in the relaxation of blood vessels which in turn would help fight heart disease