: an amino acid C5H9NO2 that can be synthesized by animals from glutamate
Examples of proline in a Sentence
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Bone broth provides amino acids, like proline and glycine, that support tissue repair.
—
Lindsay Curtis, Health, 7 Feb. 2026
The amino acids required for collagen synthesis, particularly glycine, proline, and lysine, are readily available from a wide range of foods including eggs, fish, poultry, dairy products, legumes, soy foods and meat.
—Leeann Weintraub, Daily News, 5 Feb. 2026
The team's investigation reveals that in humans, a single amino acid substitution—from proline to serine at position 153—renders FasL vulnerable to plasmin, an enzyme frequently elevated in aggressive solid tumors like ovarian, colon and triple-negative breast cancers.
—Daniella Gray, MSNBC Newsweek, 7 July 2025
Eggs themselves are not a source of collagen—but the egg white specifically contains proline and glycine, two essential amino acids for proper collagen production.
—Alessandra Signorelli, Vogue, 1 July 2025
Notably, the bitter sensitive alleles were also nominally associated with chronic kidney diseases and a range of markers of kidney health, including urinary proline betaine levels, glomerular filtration rate, serum non-albumin protein, and glucose levels 2 h after an oral glucose challenge.
—Bronwyn Thompson, New Atlas, 15 June 2025
Spot On! Advertisement Advertisement There are also 11 non-essential amino acids—alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine—that can be produced by your body.
—Stacey Colino, Time, 27 May 2025
Bone broth’s collagen and amino acids, like glycine and proline, may support cartilage health and reduce inflammation.
—Sandra Rose Salathe, Flow Space, 26 Dec. 2024
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Lindsay Curtis, Health, 7 Feb. 2026
The amino acids required for collagen synthesis, particularly glycine, proline, and lysine, are readily available from a wide range of foods including eggs, fish, poultry, dairy products, legumes, soy foods and meat.
—Leeann Weintraub, Daily News, 5 Feb. 2026
The team's investigation reveals that in humans, a single amino acid substitution—from proline to serine at position 153—renders FasL vulnerable to plasmin, an enzyme frequently elevated in aggressive solid tumors like ovarian, colon and triple-negative breast cancers.
—Daniella Gray, MSNBC Newsweek, 7 July 2025
Eggs themselves are not a source of collagen—but the egg white specifically contains proline and glycine, two essential amino acids for proper collagen production.
—Alessandra Signorelli, Vogue, 1 July 2025
Notably, the bitter sensitive alleles were also nominally associated with chronic kidney diseases and a range of markers of kidney health, including urinary proline betaine levels, glomerular filtration rate, serum non-albumin protein, and glucose levels 2 h after an oral glucose challenge.
—Bronwyn Thompson, New Atlas, 15 June 2025
Spot On! Advertisement Advertisement There are also 11 non-essential amino acids—alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine—that can be produced by your body.
—Stacey Colino, Time, 27 May 2025
Bone broth’s collagen and amino acids, like glycine and proline, may support cartilage health and reduce inflammation.
—Sandra Rose Salathe, Flow Space, 26 Dec. 2024
Cite this Entry
“Proline.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/proline. Accessed 22 Feb. 2026.
Copy CitationMedical Definition
proline
noun
pro·line
ˈprō-ˌlēn 
: an amino acid C5H9NO2 that can be synthesized by animals from glutamate
—abbreviation Pro
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