# Prunasin > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Prunasin > Markdown URL: https://mediated.wiki/source/Prunasin.md > Source: https://en.wikipedia.org/wiki/Prunasin > Source revision: 1320620765 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{Chembox | ImageFile = Prunasin.svg | ImageSize = 200px | ImageAlt = Chemical structure of prunasin | IUPACName = (''R'')-(β-D-Glucopyranosyloxy)(phenyl)acetonitrile | SystematicName = (''R'')-Phenyl{[(2''R'',3''R'',4''S'',5''S'',6''R'')-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}acetonitrile | OtherNames = (''R'')-Prunasin
D-Prunasin
D-Mandelonitrile-β-D-glucoside
Prulaurasin Laurocerasin
Sambunigrin | Section1 = {{Chembox Identifiers | CASNo = 99-18-3 | CASNo_Ref = {{cascite|correct|CAS}} | UNII_Ref = {{fdacite|correct|FDA}} | UNII = 14W4BPM5FB | PubChem = 119033 | EINECS = 202-738-0 | ChemSpiderID = 106360 | SMILES = C1=CC=C(C=C1)[C@H](C#N)O[C@H]2[C@@H]([C@H]([C@@H]([C@H](O2)CO)O)O)O | InChI = 1/C14H17NO6/c15-6-9(8-4-2-1-3-5-8)20-14-13(19)12(18)11(17)10(7-16)21-14/h1-5,9-14,16-19H,7H2/t9-,10+,11+,12-,13+,14+/m0/s1 | InChIKey = ZKSZEJFBGODIJW-GMDXDWKABY | StdInChI = 1S/C14H17NO6/c15-6-9(8-4-2-1-3-5-8)20-14-13(19)12(18)11(17)10(7-16)21-14/h1-5,9-14,16-19H,7H2/t9-,10+,11+,12-,13+,14+/m0/s1 | StdInChIKey = ZKSZEJFBGODIJW-GMDXDWKASA-N | RTECS = | MeSHName = | ChEBI = 17396 | KEGG = C00844 }} | Section2 = {{Chembox Properties | C=14 | H=17 | N=1 | O=6 | Appearance = | Density = | MeltingPt = | BoilingPt = | Solubility = }} | Section3 = {{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }} '''(''R'')-prunasin''' is a [cyanogenic glycoside](/source/cyanogenic_glycoside) related to [amygdalin](/source/amygdalin). Chemically, it is the [glucoside](/source/glucoside) of (''R'')-[mandelonitrile](/source/mandelonitrile). == Natural occurrences == Prunasin is found in species in the genus ''Prunus'' such as ''[Prunus japonica](/source/Prunus_japonica)'' or ''[P. maximowiczii](/source/Prunus_maximowiczii)'' and in [bitter almond](/source/bitter_almond)s.{{Cite journal|last1=Sánchez-Pérez|first1=Raquel|last2=Belmonte|first2=Fara Sáez|last3=Borch|first3=Jonas|last4=Dicenta|first4=Federico|last5=Møller|first5=Birger Lindberg|last6=Jørgensen|first6=Kirsten|date=April 2012|title=Prunasin Hydrolases during Fruit Development in Sweet and Bitter Almonds|journal=Plant Physiology|language=en|volume=158|issue=4|pages=1916–1932|doi=10.1104/pp.111.192021|issn=0032-0889|pmc=3320195|pmid=22353576}} It is also found in leaves and stems of ''[Olinia ventosa](/source/Olinia_ventosa)'', ''[O. radiata](/source/Olinia_radiata)'', ''[O. emarginata](/source/Olinia_emarginata)'' and ''[O. rochetiana](/source/Olinia_rochetiana)''{{cite journal|last1=Nahrstedt|first1=Adolf|last2=Rockenbach|first2=Jürgen|year=1993|title=Occurrence of the cyanogenic glucoside prunasin and II corresponding mandelic acid amide glucoside in Olinia species (oliniaceae)|journal=Phytochemistry|volume=34|issue=2|pages=433|doi=10.1016/0031-9422(93)80024-M|bibcode=1993PChem..34..433N }} and in ''[Acacia greggii](/source/Acacia_greggii)''. It is a biosynthetic precursor of and intermediate in the biosynthesis of [amygdalin](/source/amygdalin), the [chemical compound](/source/chemical_compound) responsible for the taste of [bitter almond](/source/Bitter_Almond).{{Cn|date=September 2023}} It is also found in [dandelion coffee](/source/dandelion_coffee), a coffee substitute.{{Cn|date=September 2023}} === Sambunigrin === Sambunigrin, a [diastereomer](/source/diastereomer) of prunasin derived from (''S'')-mandelonitrile instead of it the (''R'')-isomer, has been isolated from leaves of the [elder tree](/source/Sambucus_nigra) (''Sambucus nigra'').{{citation|author=Andrew Pengelly|title=The Constituents of Medicinal Plants|pages=44–45|year=2004|edition=2nd|publisher=Allen & Unwin|isbn=978-1-74114-052-1}} Sambunigrin is present in the leaves and stems of elder at a 1:3 ratio of sambunigrin to prunasin, and 2:5 in the immature seed.{{Cite journal|last1=Miller|first1=Rebecca E.|last2=Gleadow|first2=Roslyn M.|last3=Woodrow|first3=Ian E.|date=2004|title=Cyanogenesis in tropical Prunus turneriana: characterisation, variation and response to low light|url=http://www.publish.csiro.au/?paper=FP03218|journal=Functional Plant Biology|language=en|volume=31|issue=5|pages=491–503|doi=10.1071/FP03218|pmid=32688921|bibcode=2004FunPB..31..491M |issn=1445-4408|url-access=subscription}} It is not found in the root. == Biosynthesis == === Overview === (''R'')-Prunasin begins with the common amino acid [phenylalanine](/source/phenylalanine), which in plants is produced via the [Shikimate pathway](/source/Shikimate_pathway) in [primary metabolism](/source/Metabolism). The pathway is catalyzed mainly by two [cytochrome P450](/source/cytochrome_P450) (CYP) enzymes and a [UDP-glucosyltransferase](/source/UDP-glucosyltransferase) (UGT). After (''R'')-prunasin is formed, it is either converted into [amygdalin](/source/amygdalin) by an additional UDP-glucosyltransferase or degraded into [benzaldehyde](/source/benzaldehyde) and hydrogen cyanide. Researchers have shown that the accumulation (or lack of) of prunasin and amygdalin in the almond kernel is responsible for sweet and bitter genotypes. Because amygdalin is responsible for the bitter almond taste, almond growers have selected [genotype](/source/genotype)s which minimize the biosynthesis of amygdalin. The CYP enzymes responsible for generation of prunasin are conserved across ''Prunus'' species.{{Cite journal|last1=Thodberg|first1=Sara|last2=Del Cueto|first2=Jorge|last3=Mazzeo|first3=Rosa|last4=Pavan|first4=Stefano|last5=Lotti|first5=Concetta|last6=Dicenta|first6=Federico|last7=Jakobsen Neilson|first7=Elizabeth H.|last8=Møller|first8=Birger Lindberg|last9=Sánchez-Pérez|first9=Raquel|date=November 2018|title=Elucidation of the Amygdalin Pathway Reveals the Metabolic Basis of Bitter and Sweet Almonds (Prunus dulcis)1[OPEN]|journal=Plant Physiology|volume=178|issue=3|pages=1096–1111|doi=10.1104/pp.18.00922|issn=0032-0889|pmc=6236625|pmid=30297455}} There is a correlation between high concentration of prunasin in the vegetative regions of the plant and the sweetness of the almond, which is relevant to the [almond](/source/almond) agricultural industry. In almonds, the amygdalin biosynthetic [gene](/source/gene)s are [expressed](/source/Gene_expression) at different levels in the tegument (mother tissue, or outer section) and [cotyledon](/source/cotyledon) (kernel, or father tissue), and vary significantly during almond [ontogeny](/source/ontogeny).{{Cite journal|last1=Sánchez-Pérez|first1=Raquel|last2=Jørgensen|first2=Kirsten|last3=Olsen|first3=Carl Erik|last4=Dicenta|first4=Federico|last5=Møller|first5=Birger Lindberg|date=March 2008|title=Bitterness in Almonds|journal=Plant Physiology|volume=146|issue=3|pages=1040–1052|doi=10.1104/pp.107.112979|issn=0032-0889|pmc=2259050|pmid=18192442}}{{Cite journal|last1=Neilson|first1=Elizabeth H.|last2=Goodger|first2=Jason Q.D.|last3=Motawia|first3=Mohammed Saddik|last4=Bjarnholt|first4=Nanna|last5=Frisch|first5=Tina|last6=Olsen|first6=Carl Erik|last7=Møller|first7=Birger Lindberg|last8=Woodrow|first8=Ian E.|date=December 2011|title=Phenylalanine derived cyanogenic diglucosides from Eucalyptus camphora and their abundances in relation to ontogeny and tissue type|url=https://linkinghub.elsevier.com/retrieve/pii/S0031942211003888|journal=Phytochemistry|language=en|volume=72|issue=18|pages=2325–2334|doi=10.1016/j.phytochem.2011.08.022|pmid=21945721 |bibcode=2011PChem..72.2325N |url-access=subscription}} The biosynthesis of prunasin occurs in the tegument, then transported to other tissues for conversion to amygdalin or degraded. === Biosynthesis of (''R'')-prunasin === alt=|thumb|880x880px|Biosynthetic pathway for the production of (R)-prunasin in ''Prunus'' species (top) and ''Eucalyptus cladocalyx'' (bottom) ==== Biosynthesis of (''R'')-prunasin in ''Prunus dulcis'' ==== L-phenylalanine is first hydroxylated by CYP79D16, followed by a decarboxylation and dehydration, forming the ''E-''oxime phenylacetaldoxime.{{Cite journal|last1=Yamaguchi|first1=Takuya|last2=Yamamoto|first2=Kazunori|last3=Asano|first3=Yasuhisa|date=September 2014|title=Identification and characterization of CYP79D16 and CYP71AN24 catalyzing the first and second steps in l-phenylalanine-derived cyanogenic glycoside biosynthesis in the Japanese apricot, Prunus mume Sieb. et Zucc.|url=http://link.springer.com/10.1007/s11103-014-0225-6|journal=Plant Molecular Biology|language=en|volume=86|issue=1–2|pages=215–223|doi=10.1007/s11103-014-0225-6|pmid=25015725|bibcode=2014PMolB..86..215Y |s2cid=14884838|issn=0167-4412|url-access=subscription}} Next, CYP71AN24 catalyzes the rearrangement of the ''E-''oxime to the ''Z-''oxime followed by a dehydration and a hydroxylation to form mandelonitrile. Finally, UGT85A19 or UGT94AF3 utilize UDP-glucose to glycosylate mandelonitrile, forming (''R'')-prunasin. After generating (''R'')-prunasin, the product is further [glycosylated](/source/Glycosylation) into amygdalin by either [isoform](/source/Protein_isoform) UGT94AF1 or UGT94AF2. Expression of UGTAF1/2 and prunasin [hydrolase](/source/hydrolase)s results in a low overall concentration of (''R'')-prunasin in almond tissues. An alpha-[glucosidase](/source/Glucosidases) or prunasin hydrolase can convert (''R'')-prunasin to mandelonitrile, its precursor, which can then be spontaneously or enzymatically hydrolyzed to benzaldehyde and hydrogen cyanide.{{Cite journal|last1=Zhou|first1=Jiming|last2=Hartmann|first2=Stefanie|last3=Shepherd|first3=Brianne K.|last4=Poulton|first4=Jonathan E.|date=2002-07-01|title=Investigation of the Microheterogeneity and Aglycone Specificity-Conferring Residues of Black Cherry Prunasin Hydrolases|journal=Plant Physiology|language=en|volume=129|issue=3|pages=1252–1264|doi=10.1104/pp.010863|issn=0032-0889|pmc=166519|pmid=12114579}} ==== Biosynthesis of (''R'')-prunasin in ''Eucalyptus cladocalyx'' ==== The biosynthesis of (''R'')-prunasin in ''E. cladocalyx'', the [sugar gum tree](/source/Eucalyptus_cladocalyx), has been shown to synthesize (''R'')-prunasin using an additional intermediate, [phenylacetonitrile](/source/Benzyl_cyanide), using CYP706C55.{{Cite journal|last1=Hansen|first1=Cecilie Cetti|last2=Sørensen|first2=Mette|last3=Veiga|first3=Thiago A.M.|last4=Zibrandtsen|first4=Juliane F.S.|last5=Heskes|first5=Allison M.|last6=Olsen|first6=Carl Erik|last7=Boughton|first7=Berin A.|last8=Møller|first8=Birger Lindberg|last9=Neilson|first9=Elizabeth H.J.|date=November 2018|title=Reconfigured Cyanogenic Glucoside Biosynthesis in Eucalyptus cladocalyx Involves a Cytochrome P450 CYP706C55|journal=Plant Physiology|language=en|volume=178|issue=3|pages=1081–1095|doi=10.1104/pp.18.00998|issn=0032-0889|pmc=6236593|pmid=30297456}} The pathway proceeds similarly to the pathway in ''Prunus'' species, where the multifunctional CYP79A125 catalyzes the conversion of L-phenylalanine to phenylacetaldoxime. Then, CYP706C55 catalyzes the [dehydration](/source/Dehydration_reaction) of phenylacetaldoxime to phenylacetonitrile. Phenylacetonitrile is then hydroxylated by CYP71B103 to [mandelonitrile](/source/mandelonitrile). After generating mandelonitrile, UGT85A59 transfers glucose to yield (''R'')-prunasin. == Metabolic Pathway Interactions == As (''R'')-prunasin is a product of secondary metabolism, its generation and degradation affect multiple metabolic pathways by consuming L-phenylalanine or increasing quantities of benzaldehyde and toxic hydrogen cyanide through prunasin degradation. Metabolic profiling in almond, cassava, and sorghum identified a potential recycling mechanism where (''R'')-prunasin and other cyanogen glycosides may be utilized for nitrogen storage and nitrogen recycling without generating HCN.{{Cite journal|last1=Pičmanová|first1=Martina|last2=Neilson|first2=Elizabeth H.|last3=Motawia|first3=Mohammed S.|last4=Olsen|first4=Carl Erik|last5=Agerbirk|first5=Niels|last6=Gray|first6=Christopher J.|last7=Flitsch|first7=Sabine|last8=Meier|first8=Sebastian|last9=Silvestro|first9=Daniele|last10=Jørgensen|first10=Kirsten|last11=Sánchez-Pérez|first11=Raquel|date=2015-08-01|title=A recycling pathway for cyanogenic glycosides evidenced by the comparative metabolic profiling in three cyanogenic plant species|url=https://portlandpress.com/biochemj/article/469/3/375/48553/A-recycling-pathway-for-cyanogenic-glycosides|journal=Biochemical Journal|language=en|volume=469|issue=3|pages=375–389|doi=10.1042/BJ20150390|pmid=26205491 |s2cid=206152311 |issn=0264-6021|url-access=subscription}} In 2017, researchers used stable isotope labeling to demonstrate that 13C-labeled L-phenylalanine incorporated in (''R'')-prunasin could be converted to benzaldehyde and to salicylic acid using mandelonitrile as an intermediate.{{Cite journal|last1=Diaz-Vivancos|first1=Pedro|last2=Bernal-Vicente|first2=Agustina|last3=Cantabella|first3=Daniel|last4=Petri|first4=Cesar|last5=Hern�ndez|first5=Jos� Antonio|date=2017-12-01|title=Metabolomics and Biochemical Approaches Link Salicylic Acid Biosynthesis to Cyanogenesis in Peach Plants|url=http://academic.oup.com/pcp/article/58/12/2057/4222594|journal=Plant and Cell Physiology|language=en|volume=58|issue=12|pages=2057–2066|doi=10.1093/pcp/pcx135|pmid=29036663 |issn=0032-0781|doi-access=free|hdl=10317/7678|hdl-access=free}} == Toxicity == The toxicity of prunasin is based in its degradation products: (''R'')-prunasin is [hydrolyzed](/source/Hydrolysis) to form [benzaldehyde](/source/benzaldehyde) and [hydrogen cyanide](/source/hydrogen_cyanide), which causes toxicity. Plants containing prunasin may therefore be toxic to animals, particularly [ruminant](/source/ruminant)s.{{Cite book|author=Peter R. Cheeke|title=Toxicants of Plant Origin: Glycosides|date=1989|publisher=CRC Press|volume=2|page=137}} To degrade amygdalin to prunasin, [amygdalin beta-glucosidase](/source/amygdalin_beta-glucosidase) hydrolyzes the disaccharide to produce (''R'')-prunasin and D-glucose. Then, [prunasin beta-glucosidase](/source/prunasin_beta-glucosidase) uses (''R'')-prunasin and water to produce D-[glucose](/source/glucose) and [mandelonitrile](/source/mandelonitrile). After generating the [aglycone](/source/aglycone) [mandelonitrile](/source/mandelonitrile), then a [mandelonitrile lyase](/source/mandelonitrile_lyase) can degrade the compound into [benzaldehyde](/source/benzaldehyde) and [hydrogen cyanide](/source/hydrogen_cyanide).{{Cn|date=September 2023}} == References == {{Reflist}} Category:Cyanogenic glycosides Category:Plant toxins Category:Glucosides --- Adapted from the Wikipedia article [Prunasin](https://en.wikipedia.org/wiki/Prunasin) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Prunasin?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.