Patatin

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Potato tubers

Patatin is a family of glycoproteins found in potatoes (Solanum tuberosum) and is also known as tuberin as it is commonly found within vacuoles of parenchyma tissue in the tuber of the plant. They consist of about 366 amino acids all making up and isoelectric point of 4.9. They have a molecular weight ranging from 40 to 45 kDa, but are commonly found as a 80kDa dimer. [1] The main function of patatin is as a storage protein but it also has lipase activity and can cleave fatty acids from membrane lipids. [2] [3] The patatin protein makes up about 40% of the soluble protein in potato tubers. [4] Members of this protein family have also been found in animals.

Contents

Allergy

Patatin is identified as a major cause of potato allergy. [5] It has found to be similar to latex, and when in contact with open skin, there has been an increase of immunoglobulin E which causes some allergic reactions and symptoms, such as asthmatic symptoms, or atopic dermatitis. [6] It is unclear as to why the plant does this, however it could be a potential defense mechanism against insects. [7]

Function

Functionally, patatin serves as a key contributor to the antioxidant activity in potato tubers, in order to keep the potato fresh. Additionally, they function as acyl hydrolases, which breaks down different types of substrates. Notably, patatins also demonstrate β-1,3-glucanase activity, suggesting their involvement in breaking down polysaccharides. This diverse enzymatic activity contributes to ensuring the nutritional composition of the potato. Beyond their role as storage proteins, patatins play a significant part in the plant's defense mechanisms against pests and fungal pathogens. The galactolipase and β-1,3-glucanase activities exhibited by patatins are believed to contribute to the plant's resistance to external threats. This dual functionality underscores the importance of patatins in safeguarding the potato plant against potential environmental challenges. [8]

Beyond its role as a storage protein, patatin's functions extend to antioxidant activity and categorization as an esterase enzyme complex. It demonstrates enzymatic activity in lipid metabolism through lipid acyl hydrolases (LAHs) and acyl transferases. This activity varies across potato cultivars, extraction techniques, and fatty acid substrates. [9]

Structure

PDB 1oxw EBI.jpg

The patatin genes are located at a single major locus, comprising both functional and non-functional genes. Patatin isoforms exhibit considerable variability among different potato cultivars. Patatin's primary residence in the vacuole, alongside protease inhibitor variants, positions it as a major player in potato tuber proteins. The ngLOC software predicts 296 vacuolar proteins, with 450 putative vacuolar proteins identified through mass spectrometric sequencing. Notably, the tuber vacuole is recognized as a protein storage vacuole, with a distinct absence of proteolytic or glycolytic enzymes. Structurally, patatin emerges as a tertiary stabilized protein, exhibiting stability up to 45 °C. Beyond this threshold, its secondary structure begins to unfold, with the α-helical portion denaturing at 55 °C. This vulnerability to temperature changes highlights the delicate balance in maintaining its structural integrity. [10]

Patatin's hydrolase activity, attributed to its parallel β-sheet core with a catalytic serine located in the nucleophilic elbow loop, places it within the hydrolase family. This core structure is crucial for its lipid acyl hydrolase (LAH) activity, providing insights into its enzymatic functions and potential participation in plant defenses. [11]

There is a study delves into the multifaceted properties of patatin, the predominant protein in potatoes, revealing its structural diversity through the identification of several isoforms. Notably rich in essential amino acids, patatin emerges as a valuable source of nutrition. The glycoprotein nature of patatin, characterized by O-linked glycosylation, incorporates various monosaccharides, including fucose, indicating a fucosylated glycan structural feature. The specific binding of patatin to AAL, a fucose-affine lectin, underscores its distinctive glycan composition. Moving beyond its molecular characteristics, the research explores the regulatory effects of patatin on lipid metabolism, fat catabolism, fat absorption, and lipase activity in zebrafish larvae subjected to high-fat feeding. Results suggest that patatin, at a concentration of 37.0 μg/mL, promotes lipid decomposition metabolism by 23% and exhibits inhibitory effects on lipase activity and fat absorption, positioning it as a potential natural constituent with anti-obesity properties. These findings illuminate the diverse facets of patatin, shedding light on its nutritional significance and its prospective role in combating obesity. [12]

Isoforms

Patatin is a complex assembly of proteins represented by two multigene families: class I in large concentrations in the tuber and class II in smaller concentrations throughout the potato plant. Isoforms A, B, C, and D exhibit charge-based differences, with isoform A presenting the lowest surface charge. These isoforms, homologous in nature, differ in molecular masses and ratios, showcasing their structural diversity.

Glycosylation

Patatin isoforms undergo glycosylation, impacting their molecular masses and contributing to variations between isoforms. Experimental discrepancies in molar mass differences indicate potential glycosylation between protein and carbohydrates in potatoes. This glycosylation may play a role in the protein's functional characteristics. [11]

Patatin-like phospholipase

The patatin-like phospholipase (PNPLA) domain, found in proteins encoding patatin, is widespread across diverse life forms, spanning eukaryotes and prokaryotes. These proteins are involved in a variety of biological functions, encompassing sepsis induction, host colonization, triglyceride metabolism, and membrane trafficking. Key features of PNPLA domain-containing proteins include their lipase and transacylase properties, signifying their significant roles in maintaining lipid and energy homeostasis across different organisms and biological contexts. [13]

Related Research Articles

<span class="mw-page-title-main">Lipid</span> Substance of biological origin that is soluble in nonpolar solvents

Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins, monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries, and in nanotechnology.

<span class="mw-page-title-main">Amylopectin</span> Chemical compound

Amylopectin is a water-insoluble polysaccharide and highly branched polymer of α-glucose units found in plants. It is one of the two components of starch, the other being amylose.

<span class="mw-page-title-main">Acetyl-CoA carboxylase</span> Enzyme that regulates the metabolism of fatty acids

Acetyl-CoA carboxylase (ACC) is a biotin-dependent enzyme that catalyzes the irreversible carboxylation of acetyl-CoA to produce malonyl-CoA through its two catalytic activities, biotin carboxylase (BC) and carboxyltransferase (CT). ACC is a multi-subunit enzyme in most prokaryotes and in the chloroplasts of most plants and algae, whereas it is a large, multi-domain enzyme in the cytoplasm of most eukaryotes. The most important function of ACC is to provide the malonyl-CoA substrate for the biosynthesis of fatty acids. The activity of ACC can be controlled at the transcriptional level as well as by small molecule modulators and covalent modification. The human genome contains the genes for two different ACCs—ACACA and ACACB.

Lipid metabolism is the synthesis and degradation of lipids in cells, involving the breakdown and storage of fats for energy and the synthesis of structural and functional lipids, such as those involved in the construction of cell membranes. In animals, these fats are obtained from food and are synthesized by the liver. Lipogenesis is the process of synthesizing these fats. The majority of lipids found in the human body from ingesting food are triglycerides and cholesterol. Other types of lipids found in the body are fatty acids and membrane lipids. Lipid metabolism is often considered the digestion and absorption process of dietary fat; however, there are two sources of fats that organisms can use to obtain energy: from consumed dietary fats and from stored fat. Vertebrates use both sources of fat to produce energy for organs such as the heart to function. Since lipids are hydrophobic molecules, they need to be solubilized before their metabolism can begin. Lipid metabolism often begins with hydrolysis, which occurs with the help of various enzymes in the digestive system. Lipid metabolism also occurs in plants, though the processes differ in some ways when compared to animals. The second step after the hydrolysis is the absorption of the fatty acids into the epithelial cells of the intestinal wall. In the epithelial cells, fatty acids are packaged and transported to the rest of the body.

<span class="mw-page-title-main">Diacylglycerol lipase</span> Enzyme that breaks down diacylglycerol in many organisms.

Diacylglycerol lipase, also known as DAG lipase, DAGL, or DGL, is an enzyme that catalyzes the hydrolysis of diacylglycerol, releasing a free fatty acid and monoacylglycerol:

diacylglycerol + H2O ⇌ monoacylglycerol + free fatty acid

<span class="mw-page-title-main">Hormone-sensitive lipase</span> Enzyme

Hormone-sensitive lipase (EC 3.1.1.79, HSL), also previously known as cholesteryl ester hydrolase (CEH), sometimes referred to as triacylglycerol lipase, is an enzyme that, in humans, is encoded by the LIPE gene, and catalyzes the following reaction:

<span class="mw-page-title-main">Acyloxyacyl hydrolase</span> Protein family

The enzyme acyloxyacyl hydrolase (EC 3.1.1.77, AOAH) was discovered because it catalyzes the reaction

Sterol O-acyltransferase is an intracellular protein located in the endoplasmic reticulum that forms cholesteryl esters from cholesterol.

<span class="mw-page-title-main">Patatin-like phospholipase</span>

Family of patatin-like phospholipases consists of various patatin glycoproteins from the total soluble protein from potato tubers, and also some proteins found in vertebrates. Patatin is a storage protein but it also has the enzymatic activity of phospholipase, catalysing the cleavage of fatty acids from membrane lipids.

<span class="mw-page-title-main">Carboxylesterase 1</span> Protein-coding gene in the species Homo sapiens

Liver carboxylesterase 1 also known as carboxylesterase 1 is an enzyme that in humans is encoded by the CES1 gene. The protein is also historically known as serine esterase 1 (SES1), monocyte esterase and cholesterol ester hydrolase (CEH). Three transcript variants encoding three different isoforms have been found for this gene. The various protein products from isoform a, b and c range in size from 568, 567 and 566 amino acids long, respectively.

<span class="mw-page-title-main">Adipose triglyceride lipase</span> Mammalian protein found in Homo sapiens

Adipose triglyceride lipase, also known as patatin-like phospholipase domain-containing protein 2 and ATGL, is an enzyme that in humans is encoded by the PNPLA2 gene. ATGL catalyses the first reaction of lipolysis, where triacylglycerols are hydrolysed to diacylglycerols.

<span class="mw-page-title-main">ACOT4</span> Protein-coding gene in the species Homo sapiens

Acyl-coenzyme A thioesterase 4 is an enzyme that in humans is encoded by the ACOT4 gene.

<span class="mw-page-title-main">ACOT11</span> Protein-coding gene in the species Homo sapiens

Acyl-coenzyme A thioesterase 11 also known as StAR-related lipid transfer protein 14 (STARD14) is an enzyme that in humans is encoded by the ACOT11 gene. This gene encodes a protein with acyl-CoA thioesterase activity towards medium (C12) and long-chain (C18) fatty acyl-CoA substrates which relies on its StAR-related lipid transfer domain. Expression of a similar murine protein in brown adipose tissue is induced by cold exposure and repressed by warmth. Expression of the mouse protein has been associated with obesity, with higher expression found in obesity-resistant mice compared with obesity-prone mice. Alternative splicing results in two transcript variants encoding different isoforms.

<span class="mw-page-title-main">PNPLA3</span> Protein-coding gene in the species Homo sapiens

Patatin-like phospholipase domain-containing protein 3 (PNPLA3), also known as adiponutrin (ADPN), acylglycerol O-acyltransferase or calcium-independent phospholipase A2-epsilon (iPLA2-epsilon) is an enzyme that in humans is encoded by the PNPLA3 gene.

<span class="mw-page-title-main">Lipase</span> Class of enzymes which cleave fats via hydrolysis

In biochemistry, lipase refers to a class of enzymes that catalyzes the hydrolysis of fats. Some lipases display broad substrate scope including esters of cholesterol, phospholipids, and of lipid-soluble vitamins and sphingomyelinases; however, these are usually treated separately from "conventional" lipases. Unlike esterases, which function in water, lipases "are activated only when adsorbed to an oil–water interface". Lipases perform essential roles in digestion, transport and processing of dietary lipids in most, if not all, organisms.

<span class="mw-page-title-main">Plant lipid transfer proteins</span>

Plant lipid transfer proteins, also known as plant LTPs or PLTPs, are a group of highly-conserved proteins of about 7-9kDa found in higher plant tissues. As its name implies, lipid transfer proteins facilitate the shuttling of phospholipids and other fatty acid groups between cell membranes. LTPs are divided into two structurally related subfamilies according to their molecular masses: LTP1s (9 kDa) and LTP2s (7 kDa). Various LTPs bind a wide range of ligands, including fatty acids with a C10–C18 chain length, acyl derivatives of coenzyme A, phospho- and galactolipids, prostaglandin B2, sterols, molecules of organic solvents, and some drugs.

<span class="mw-page-title-main">LYPLAL1</span> Protein-coding gene in the species Homo sapiens

Lysophospholipase-like 1 is a protein in humans that is encoded by the LYPLAL1 gene. The protein is a α/β-hydrolase of uncharacterized metabolic function. Genome-wide association studies in humans have linked the gene to fat distribution and waist-to-hip ratio. The protein's enzymatic function is unclear. LYPLAL1 was reported to act as a triglyceride lipase in adipose tissue and another study suggested that the protein may play a role in the depalmitoylation of calcium-activated potassium channels. However, LYPLAL1 does not depalmitoylate the oncogene Ras and a structural and enzymatic study concluded that LYPLAL1 is generally unable to act as a lipase and is instead an esterase that prefers short-chain substrates, such as acetyl groups. Structural comparisons have suggested that LYPLAL1 might be a protein deacetylase, but this has not been experimentally tested.

Protein <i>O</i>-GlcNAcase Protein-coding gene in the species Homo sapiens

Protein O-GlcNAcase (EC 3.2.1.169, OGA, glycoside hydrolase O-GlcNAcase, O-GlcNAcase, BtGH84, O-GlcNAc hydrolase) is an enzyme with systematic name (protein)-3-O-(N-acetyl-D-glucosaminyl)-L-serine/threonine N-acetylglucosaminyl hydrolase. OGA is encoded by the OGA gene. This enzyme catalyses the removal of the O-GlcNAc post-translational modification in the following chemical reaction:

  1. [protein]-3-O-(N-acetyl-β-D-glucosaminyl)-L-serine + H2O ⇌ [protein]-L-serine + N-acetyl-D-glucosamine
  2. [protein]-3-O-(N-acetyl-β-D-glucosaminyl)-L-threonine + H2O ⇌ [protein]-L-threonine + N-acetyl-D-glucosamine
<span class="mw-page-title-main">ACOT1</span> Protein-coding gene in the species Homo sapiens

Acyl-CoA thioesterase 1 is a protein that in humans is encoded by the ACOT1 gene.

Nutritional immunology is a field of immunology that focuses on studying the influence of nutrition on the immune system and its protective functions. Indeed, every organism will under nutrient-poor conditions "fight" for the precious micronutrients and conceal them from invading pathogens. As such, bacteria, fungi, plants secrete for example iron chelators (siderophores) to acquire iron from their surrounding

References

  1. ↑ Racusen D, Weller DL (1984). "Molecular Weight of Patatin, a Major Potato Tuber Protein1". Journal of Food Biochemistry. 8 (2): 103–107. doi: 10.1111/j.1745-4514.1984.tb00318.x . ISSN   1745-4514.
  2. ↑ Shewry PR (June 2003). "Tuber storage proteins". Annals of Botany. 91 (7): 755–769. doi:10.1093/aob/mcg084. PMC   4242388 . PMID   12730067.
  3. ↑ Bánfalvi Z, Kostyál Z, Barta E (November 1994). "Solanum brevidens possesses a non-sucrose-inducible patatin gene". Molecular & General Genetics. 245 (4): 517–522. doi:10.1007/BF00302265. PMID   7808402. S2CID   6862380.
  4. ↑ Mignery GA, Pikaard CS, Park WD (1988). "Molecular characterization of the patatin multigene family of potato". Gene. 62 (1): 27–44. doi:10.1016/0378-1119(88)90577-X. PMID   3371664.
  5. ↑ Chipps BE (5 March 2000). "Food Allergy: New Insights and Management Strategies". Potato Allergy. Medscape.
  6. ↑ Seppälä U, Alenius H, Turjanmaa K, Reunala T, Palosuo T, Kalkkinen N (January 1999). "Identification of patatin as a novel allergen for children with positive skin prick test responses to raw potato". The Journal of Allergy and Clinical Immunology. 103 (1 Pt 1): 165–171. doi:10.1016/s0091-6749(99)70541-5. PMID   9893201.
  7. ↑ Srivastava LM (2002). "Vegetative storage protein, tuberization, senescence, and abscission. 4. Defense related proteins.". Plant growth and development. Hormones and environment. San Diego: Academic Press. pp. 473–520. doi:10.1016/B978-012660570-9/50162-3.
  8. ↑ Waglay A, Karboune S (January 2016). "Chapter 4 - Potato Proteins: Functional Food Ingredients". In Singh J, Kaur L (eds.). Advances in Potato Chemistry and Technology (Second ed.). San Diego: Academic Press. pp. 75–104. doi:10.1016/B978-0-12-800002-1.00004-2. ISBN   978-0-12-800002-1.
  9. ↑ Kärenlampi SO, White PJ (January 2009). "Chapter 5 - Potato Proteins, Lipids, and Minerals". In Singh J, Kaur L (eds.). Advances in Potato Chemistry and Technology. San Diego: Academic Press. pp. 99–125. doi:10.1016/B978-0-12-374349-7.00005-2. ISBN   978-0-12-374349-7.
  10. ↑ González-Pérez S, Arellano JB (2009-01-01). "15 - Vegetable protein isolates". In Phillips GO, Williams PA (eds.). Handbook of Hydrocolloids. Woodhead Publishing Series in Food Science, Technology and Nutrition (Second ed.). Woodhead Publishing. pp. 383–419. doi:10.1533/9781845695873.383. hdl:10261/21904. ISBN   978-1-84569-414-2.
  11. 1 2 Alting AC, Pouvreau L, Giuseppin ML, van Nieuwenhuijzen NH (January 2011). "12 - Potato proteins". In Phillips GO, Williams PA (eds.). Handbook of Food Proteins. Woodhead Publishing Series in Food Science, Technology and Nutrition. Woodhead Publishing. pp. 316–334. doi:10.1533/9780857093639.316. ISBN   978-1-84569-758-7.
  12. ↑ Wu J, Wu Q, Yang D, Zhou M, Xu J, Wen Q, et al. (May 2021). "Patatin primary structural properties and effects on lipid metabolism". Food Chemistry. 344: 128661. doi:10.1016/j.foodchem.2020.128661. PMID   33272761. S2CID   227282218.
  13. ↑ Liu G, Zhang K, Ai J, Deng X, Hong Y, Wang X (November 2015). "Patatin-related phospholipase A, pPLAIIIα, modulates the longitudinal growth of vegetative tissues and seeds in rice". Journal of Experimental Botany. 66 (21): 6945–55. doi:10.1093/jxb/erv402. PMC   4623698 . PMID   26290597.
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