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Amino Acids Jan 2018Glycine, proline, and hydroxyproline (Hyp) contribute to 57% of total amino acids (AAs) in collagen, which accounts for one-third of proteins in animals. As the most... (Review)
Review
Glycine, proline, and hydroxyproline (Hyp) contribute to 57% of total amino acids (AAs) in collagen, which accounts for one-third of proteins in animals. As the most abundant protein in the body, collagen is essential to maintain the normal structure and strength of connective tissue, such as bones, skin, cartilage, and blood vessels. Mammals, birds, and fish can synthesize: (1) glycine from threonine, serine, choline, and Hyp; (2) proline from arginine; and (3) Hyp from proline residues in collagen, in a cell- and tissue-specific manner. In addition, livestock (e.g., pigs, cattle, and sheep) produces proline from glutamine and glutamate in the small intestine, but this pathway is absent from birds and possibly most fish species. Results of the recent studies indicate that endogenous synthesis of glycine, proline, and Hyp is inadequate for maximal growth, collagen production, or feed efficiency in pigs, chickens, and fish. Although glycine, proline and Hyp, and gelatin can be used as feed additives in animal diets, these ingredients except for glycine are relatively expensive, which precludes their inclusion in practical rations. Alternatively, hydrolyzed feather meal (HFM), which contains 9% glycine, 5% Hyp, and 12% proline, holds great promise as a low cost but abundant dietary source of glycine, Hyp, and proline for ruminants and nonruminants. Because HFM is deficient in most AAs, future research efforts should be directed at improving the bioavailability of its AAs and the balance of AAs in HFM-supplemented diets. Finally, HFM may be used as a feed additive to prevent or ameliorate connective tissue disorders in domestic and aquatic animals.
Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Collagen; Food, Fortified; Glycine; Hydroxyproline; Metabolic Networks and Pathways; Proline; Species Specificity
PubMed: 28929384
DOI: 10.1007/s00726-017-2490-6 -
JCI Insight Aug 2023Proline and its synthesis enzyme pyrroline-5-carboxylate reductase 1 (PYCR1) are implicated in epithelial-mesenchymal transition (EMT), yet how proline and PYCR1...
Proline and its synthesis enzyme pyrroline-5-carboxylate reductase 1 (PYCR1) are implicated in epithelial-mesenchymal transition (EMT), yet how proline and PYCR1 function in allergic asthmatic airway remodeling via EMT has not yet been addressed to our knowledge. In the present study, increased levels of plasma proline and PYCR1 were observed in patients with asthma. Similarly, proline and PYCR1 in lung tissues were high in a murine allergic asthma model induced by house dust mites (HDMs). Pycr1 knockout decreased proline in lung tissues, with reduced airway remodeling and EMT. Mechanistically, loss of Pycr1 restrained HDM-induced EMT by modulating mitochondrial fission, metabolic reprogramming, and the AKT/mTORC1 and WNT3a/β-catenin signaling pathways in airway epithelial cells. Therapeutic inhibition of PYCR1 in wild-type mice disrupted HDM-induced airway inflammation and remodeling. Deprivation of exogenous proline relieved HDM-induced airway remodeling to some extent. Collectively, this study illuminates that proline and PYCR1 involved with airway remodeling in allergic asthma could be viable targets for asthma treatment.
Topics: Animals; Mice; Airway Remodeling; Proline; Asthma; Lung; Hypersensitivity
PubMed: 37432745
DOI: 10.1172/jci.insight.167395 -
Cell Death and Differentiation Aug 2023Solute carrier family 25 member 51 (SLC25A51) was recently identified as the mammalian mitochondrial NAD+ transporter essential for mitochondria functions. However, the...
Solute carrier family 25 member 51 (SLC25A51) was recently identified as the mammalian mitochondrial NAD+ transporter essential for mitochondria functions. However, the role of SLC25A51 in human disease, such as cancer, remains undefined. Here, we report that SLC25A51 is upregulated in multiple cancers, which promotes cancer cells proliferation. Loss of SLC25A51 elevates the mitochondrial proteins acetylation levels due to SIRT3 dysfunctions, leading to the impairment of P5CS enzymatic activity, which is the key enzyme in proline biogenesis, and the reduction in proline contents. Notably, we find fludarabine phosphate, an FDA-approved drug, is able to bind with and inhibit SLC25A51 functions, causing mitochondrial NAD decrease and proteins hyperacetylation, which could further synergize with aspirin to reinforce the anti-tumor efficacy. Our study reveals that SLC25A51 is an attractive anti-cancer target, and provides a novel drug combination of fludarabine phosphate with aspirin as a potential cancer therapy strategy.
Topics: Animals; Humans; Acetylation; Proline; Mitochondria; Sirtuin 3; Homeostasis; Mammals
PubMed: 37419986
DOI: 10.1038/s41418-023-01185-2 -
Trends in Plant Science Jan 2022Proline is a multifunctional amino acid that is accumulated in high concentrations in plants under various stress conditions. Proline accumulation is intimately... (Review)
Review
Proline is a multifunctional amino acid that is accumulated in high concentrations in plants under various stress conditions. Proline accumulation is intimately connected to many cellular processes, such as osmotic pressure, energy status, nutrient availability, changes in redox balance, and defenses against pathogens. Proline biosynthesis and catabolism is linked to photosynthesis and mitochondrial respiration, respectively. Proline can function as a signal, modulating gene expression and certain metabolic processes. We review important findings on proline metabolism and function of the last decade, giving a more informative picture about the function of this unusual amino acid in maintaining cellular homeostasis, modulating plant development, and promoting stress acclimation.
Topics: Osmotic Pressure; Photosynthesis; Plant Development; Plants; Proline
PubMed: 34366236
DOI: 10.1016/j.tplants.2021.07.009 -
The New England Journal of Medicine Sep 2022
Topics: Antiviral Agents; Drug Combinations; Humans; Lactams; Leucine; Nitriles; Proline; Recurrence; Ritonavir; Viral Load; COVID-19 Drug Treatment
PubMed: 36069818
DOI: 10.1056/NEJMc2205944 -
Journal of Wound Care Jan 2021We evaluated the effects of a specialised oral nutritional supplement (ONS) containing arginine and proline, with high vitamin A, C and E, zinc and selenium content, on... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
We evaluated the effects of a specialised oral nutritional supplement (ONS) containing arginine and proline, with high vitamin A, C and E, zinc and selenium content, on the repair of hard-to-heal wounds.
METHOD
Patients with hard-to-heal wounds were evaluated at five timepoints (S0-S4) over four consecutive weeks. At S0 patients were randomised to the specialised ONS (n=15; 25 wounds) or control (n=15; 25 wounds) groups. Posology was 200ml twice daily over the research period. Wound surface area and perimeter were monitored. In addition to the metric data, it was also possible to calculate the rate of wound contraction and the linear growth of the wound edges, looking for wound-healing predictive factors.
RESULTS
A total of 30 patients took part in the study. Mean age was 65 years and 50% of patients had diabetes. Of the total evaluated wounds, 78% were <50cm, 14% were 50-150cm and 8% were >250cm. In 96% of cases, the wounds were in the lower limbs. A statistically significant reduction (p=0.004) in surface area of the wounds due to the specialised ONS, with a performance peak between S1 and S2, was observed. This specialised ONS did not induce changes in blood pressure, blood glucose level or renal function. A mean weekly wound edge growth of 1.85mm in patients with diabetes and 3.0mm in those without diabetes was observed. These results were 2.9 and 4.6 times, respectively, higher than expected, according to the literature.
CONCLUSION
Specialised ONS can be a therapeutic option for hard-to-heal wounds.
Topics: Administration, Oral; Adult; Aged; Aged, 80 and over; Dietary Supplements; Female; Humans; Male; Middle Aged; Pressure Ulcer; Proline; Treatment Outcome; Wound Healing; Zinc
PubMed: 33439085
DOI: 10.12968/jowc.2021.30.1.26 -
Molecules and Cells Nov 2022Proline plays a multifaceted role in protein synthesis, redox balance, cell fate regulation, brain development, and other cellular and physiological processes. Here, we... (Review)
Review
Proline plays a multifaceted role in protein synthesis, redox balance, cell fate regulation, brain development, and other cellular and physiological processes. Here, we focus our review on proline metabolism in neurons, highlighting the role of dysregulated proline metabolism in neuronal dysfunction and consequently neurological and psychiatric disorders. We will discuss the association between genetic and protein function of enzymes in the proline pathway and the development of neurological and psychiatric disorders. We will conclude with a potential mechanism of proline metabolism in neuronal function and mental health.
Topics: Humans; Mental Disorders; Proline
PubMed: 36324271
DOI: 10.14348/molcells.2022.0115 -
Antioxidants & Redox Signaling Feb 2019Proline catabolism refers to the 4-electron oxidation of proline to glutamate catalyzed by the enzymes proline dehydrogenase (PRODH) and l-glutamate γ-semialdehyde... (Review)
Review
SIGNIFICANCE
Proline catabolism refers to the 4-electron oxidation of proline to glutamate catalyzed by the enzymes proline dehydrogenase (PRODH) and l-glutamate γ-semialdehyde dehydrogenase (GSALDH, or ALDH4A1). These enzymes and the intermediate metabolites of the pathway have been implicated in tumor growth and suppression, metastasis, hyperprolinemia metabolic disorders, schizophrenia susceptibility, life span extension, and pathogen virulence and survival. In some bacteria, PRODH and GSALDH are combined into a bifunctional enzyme known as proline utilization A (PutA). PutAs are not only virulence factors in some pathogenic bacteria but also fascinating systems for studying the coordination of metabolic enzymes via substrate channeling. Recent Advances: The past decade has seen an explosion of structural data for proline catabolic enzymes. This review surveys these structures, emphasizing protein folds, substrate recognition, oligomerization, kinetic mechanisms, and substrate channeling in PutA.
CRITICAL ISSUES
Major unsolved structural targets include eukaryotic PRODH, the complex between monofunctional PRODH and monofunctional GSALDH, and the largest of all PutAs, trifunctional PutA. The structural basis of PutA-membrane association is poorly understood. Fundamental aspects of substrate channeling in PutA remain unknown, such as the identity of the channeled intermediate, how the tunnel system is activated, and the roles of ancillary tunnels.
FUTURE DIRECTIONS
New approaches are needed to study the molecular and in vivo mechanisms of substrate channeling. With the discovery of the proline cycle driving tumor growth and metastasis, the development of inhibitors of proline metabolic enzymes has emerged as an exciting new direction. Structural biology will be important in these endeavors.
Topics: Animals; Biocatalysis; Humans; Models, Molecular; Molecular Structure; Proline; Proline Oxidase
PubMed: 28990412
DOI: 10.1089/ars.2017.7374 -
Cells Jul 2022In this paper, we summarize the current knowledge of the role of proline metabolism in the control of the identity of Embryonic Stem Cells (ESCs). An imbalance in... (Review)
Review
In this paper, we summarize the current knowledge of the role of proline metabolism in the control of the identity of Embryonic Stem Cells (ESCs). An imbalance in proline metabolism shifts mouse ESCs toward a stable naïve-to-primed intermediate state of pluripotency. Proline-induced cells (PiCs), also named primitive ectoderm-like cells (EPLs), are phenotypically metastable, a trait linked to a rapid and reversible relocalization of E-cadherin from the plasma membrane to intracellular membrane compartments. The ESC-to-PiC transition relies on the activation of Erk and Tgfβ/Activin signaling pathways and is associated with extensive remodeling of the transcriptome, metabolome and epigenome. PiCs maintain several properties of naïve pluripotency (teratoma formation, blastocyst colonization and 3D gastruloid development) and acquire a few traits of primed cells (flat-shaped colony morphology, aerobic glycolysis metabolism and competence for primordial germ cell fate). Overall, the molecular and phenotypic features of PiCs resemble those of an early-primed state of pluripotency, providing a robust model to study the role of metabolic perturbations in pluripotency and cell fate decisions.
Topics: Animals; Blastocyst; Cell Differentiation; Embryonic Stem Cells; Mice; Proline; Transcriptome
PubMed: 35883568
DOI: 10.3390/cells11142125 -
Combinatorial Chemistry & High... 2023L-proline is a natural amino acid having secondary amine functionality and acts as a bifunctional catalyst (organo-catalyst). The amino-functional group acts as Lewis... (Review)
Review
BACKGROUND
L-proline is a natural amino acid having secondary amine functionality and acts as a bifunctional catalyst (organo-catalyst). The amino-functional group acts as Lewis base type while carboxylic acids act as Brønsted acid type catalysts. It catalyzed different asymmetric syntheses, including known reactions such as Aldol condensation, Mannich reaction, Michael Addition, Knoevenagel condensation, Hantzsch synthesis, OXA-Michael Henry tandem, Ullmann reactions, Wieland-Miescher ketone synthesis, Robinson annulation, Biginelli reaction, α- amination. It is also an essential catalyst for synthesizing heterocyclic skeletons such as coumarin, spiro-oxindoles, imidazoles, benzimidazoles, quinoxalines, podophyllotoxin, benzothiazoles, isoxazolidines, phenothiazines, aziridine, indole, 1,5-benzodiazepines, pyridine, and quinazolines.
OBJECTIVE
In this review, we had the objective to critically summarize the use of proline and proline derivatives as catalysts of multicomponent reactions performed in various media and leading to synthetically and biologically relevant heterocycles, a very important class of compounds that constitutes over 60% of drugs and agrochemicals.
METHODS
All scholarly articles for L-Proline catalyzed reactions were retrieved from ScienceDirect, Google Scholar , PubMed, etc. Results and Conclusion: Given the importance of L-Proline based reactions, it has been observed to have tremendous applications in organic chemistry. It can also act as a 'Green catalyst'.
Topics: Proline; Chemistry, Organic; Amino Acids; Amines; Catalysis
PubMed: 35864793
DOI: 10.2174/1386207325666220720105845