|Description||White crystals or crystalline powder||White crystals or crystalline powder||—||—-|
|Loss on drying||≤0.3%||≤0.30%||≤0.3%||≤0.4%|
|Residue on ignition||≤0.1%||≤0.10%||≤0.1%||≤0.4%|
|Other amino acids||Conforms||Conforms||—||Conforms|
|Specific Rotation||-84.5°~ -86.0°||-84.5°~ -86.0°°||-84.5°~ -86.0°°||-84.3°~ -86.3°°|
L-proline is one of the 20 amino acids that are used to synthesize proteins by the human body. This amino acid is encoded in the human genetic code with the codons CCA, CCC, CCG and CCU. L-proline is the only proteinogenic amino acid that is a secondary amine, meaning that its amine nitrogen is bound to two alkyl groups. Virtually all of the proteins in the human body contain L-proline, and the only amino acids that are more abundant are alanine and glutamine. L-proline is especially important in the production of collagen, which is a primary component in skin, cartilage and bone.
The biosynthesis of L-proline uses the amino acid L-glutamate as a precursor, along with the enzymes glutamate 5-kinase and glutamate-5-semialdehyde dehydrogenase. The German chemist Richard Willstatter first synthesized proline in the laboratory in 1900 by reacting 1,3-dibromopropane with the sodium salt of diethyl malonate. The German chemist Hermann Emil Fischer isolated proline from casein in 1901 by using gamma-phthalimido-propylmalonic ester.
The biochemical actions of pure L-proline include weak agonism of the glycine receptors and some glutamate receptors. Plants also use proline to generate tissues such as pollen. Health supplements containing L-proline are often taken to support the growth of connective tissue.
Uses of L-Proline
The support of joint and skin health is one of the most significant reasons for taking L-proline supplements. It may also support muscle growth and injury recovery.
Signs You May Need L-Proline
Some conditions such as a low-protein diet, chronic injuries and illnesses may prevent you from manufacturing adequate quantities of L-proline. Endurance athletes may also benefit from L-proline supplements, especially long-distance runners. Specific signs in the skin that can indicate a deficiency of L-proline include wrinkles and sores that are slow to heal. Chronic joint discomfort due to degenerating cartilage is also a sign that you could benefit from L-proline.