: an amino acid C5H9NO2 that can be synthesized by animals from glutamate
Examples of proline in a Sentence
Recent Examples on the Web
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
This long cooking time breaks down collagen and other connective tissues, extracting minerals like calcium, magnesium and phosphorus, along with amino acids such as glycine, proline and glutamine.
—Sandra Rose Salathe, Flow Space, 26 Dec. 2024
Research suggests bone broth may be lower in , glycine, and proline (primary amino acids) than collagen supplements.8
8 Science-Backed Collagen Benefits
4.
—Jonathan Purtell, Verywell Health, 9 Oct. 2024
Meanwhile Atlantic sea kelp, proline, and botanical oils help boost collagen production and to ensure skin is more moisturized after each use.
—Kiana Murden, Vogue, 15 Aug. 2024
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
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
This long cooking time breaks down collagen and other connective tissues, extracting minerals like calcium, magnesium and phosphorus, along with amino acids such as glycine, proline and glutamine.
—Sandra Rose Salathe, Flow Space, 26 Dec. 2024
Research suggests bone broth may be lower in , glycine, and proline (primary amino acids) than collagen supplements.8
8 Science-Backed Collagen Benefits
4.
—Jonathan Purtell, Verywell Health, 9 Oct. 2024
Meanwhile Atlantic sea kelp, proline, and botanical oils help boost collagen production and to ensure skin is more moisturized after each use.
—Kiana Murden, Vogue, 15 Aug. 2024
Cite this Entry
“Proline.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/proline. Accessed 20 Jul. 2025.
Copy CitationMedical Definition
proline
noun
pro·line
ˈprō-ˌlēn 
: an amino acid C5H9NO2 that can be synthesized by animals from glutamate
—abbreviation Pro
Love words? Need even more definitions?
Merriam-Webster unabridged
Share