L-Proline: Properties, Sources, and Applications

Description

L-proline is one of the 20 amino acids used by the human body to synthesize proteins. 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 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. L-proline is one of the two forms of proline. L-Proline and D-proline are often used as asymmetric organocatalysts for various organic reactions due to their conformational rigidity compared to other amino acids. Where L-proline is a natural non-essential amino acid, D-proline is an unnatural amino acid, with one basic and one acidic center each.

In food

Proline is primarily found in many animal-sourced foods. In fact, proline constitutes about 10% of the total amino acids in collagen. As such, foods containing collagen, like bone broth, chicken wings (with the skin), pork rinds, and gelatin, are rich sources of this amino acid. Most meats, fish, and dairy foods contain proline as well.

Synthesis

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 using gamma-phthalimido-propylmalonic ester.

Uses

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.

You may like