The main difference between lysine and L lysine is that Lysine is one of the essential amino acids in humans whereas L-lysine is one of the two isomers found in a racemic mixture of lysine. Furthermore, lysine is an α-amino acid while α-carbon of the L-lysine is in the S configuration.
Lysine and L-lysine are two forms of essential amino acids in protein synthesis in humans. The two enantiomers of lysine are the L-lysine and D-lysine where L-lysine is the biologically active form of lysine.
Key Areas Covered
1. What is Lysine
– Definition, Structure, Function
2. What is L Lysine
– Definition, Structure, Function
3. What are the Similarities Between Lysine and L Lysine
– Outline of Common Features
4. What is the Difference Between Lysine and L Lysine
– Comparison of Key Differences
Key Terms
Alpha-Amino Acids, Alpha-Carbon, Enantiomers, L-Lysine, Lysine
What is Lysine
Lysine is an essential amino acid in humans, which cannot be synthesized by the body through regular metabolic processes. Therefore, it has to be included in the diet. Generally, meat, fish, dairy, and eggs contain lysine. Also, some plants such as soy and other legumes contain lysine.
Figure 1: L-Lysine
Besides, we can take lysine in the form of a dietary supplement through the mouth. Lysine supplements are supposed to enhance athletic performance. Also, it is used to prevalent the symptoms of schizophrenia, a mental disorder. It can reduce the symptoms of canker sores as well. The direct application of lysine on the skin can prevent cold sores caused by a virus called herpes simplex labialis.
What is L Lysine
L-lysine is one of the two isoforms of lysine, which is an essential amino acid in humans. The two enantiomers of lysine are L-lysine and D-lysine. The main difference between L-lysine and D-lysine is that L-lysine contains S configuration around the α-carbon while D-lysine contains the R configuration. Therefore, L-lysine is levorotatory, and D-lysine is dextrorotatory. Here, dextrorotation refers to clockwise rotation of plane-polarized light while levorotation refers to counterclockwise rotation.
Figure 2: Biosynthetic Pathways of L-Lysine
More importantly, L-lysine is the biologically active form of lysine. Therefore, all food contains L-lysine. However, D-lysine can be synthesized by chemical reactions though its intake to the body is useless.
Similarities Between Lysine and L Lysine
- Lysine and L lysine are two forms of essential amino acids required by the protein synthesis in humans.
- Both contain an α-carbon.
- Also, their side chain is a lysyl ((CH2)4NH2) residue.
Difference Between Lysine and L Lysine
Definition
Lysine refers to a basic amino acid, which is a constituent of most proteins and is an essential nutrient in the diet of vertebrates while L-lysine refers to the biologically active form of lysine. Thus, this is the fundamental difference between lysine and L lysine.
Structural Significance
Also, while lysine is an α-amino acid, L-lysine is one of the two isoforms of lysine with S configuration in the α-carbon.
Importance
Moreover, lysine is an essential amino acid in humans while L-lysine is the isoform used in the metabolic process. Hence, this is another difference between lysine and L lysine.
Conclusion
Lysine is one of the essential amino acids in humans. It cannot be synthesized by the human body and should be taken from the diet. Lysine is an α-amino acid, which consists of two enantiomers known as L-lysine and D-lysine. L-lysine has the S configuration at the α-carbon. Also, it is the biologically active form of lysine. Therefore, the main difference between lysine and L lysine is their structure and importance.
References:
1. “Lysine Effectiveness, How It Works, and Drug Interactions on EMedicineHealth.” EMedicineHealth – Health and Medical Information Produced by Doctors, Available Here.
Image Courtesy:
1. “L-Lysin – L-Lysine” By NEUROtiker – Own work (Public Domain) via Commons Wikimedia
2. “AAA DAP pathways” By Tatiana soaresdacosta – Own work (CC BY-SA 4.0) via Commons Wikimedia
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