The Enzyme Database

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EC 1.14.14.40     
Accepted name: phenylalanine N-monooxygenase
Reaction: L-phenylalanine + 2 [reduced NADPH—hemoprotein reductase] + 2 O2 = (E)-phenylacetaldoxime + 2 [oxidized NADPH—hemoprotein reductase] + CO2 + 3 H2O (overall reaction)
(1a) L-phenylalanine + [reduced NADPH—hemoprotein reductase] + O2 = N-hydroxy-L-phenylalanine + [oxidized NADPH—hemoprotein reductase] + H2O
(1b) N-hydroxy-L-phenylalanine + [reduced NADPH—hemoprotein reductase] + O2 = N,N-dihydroxy-L-phenylalanine + [oxidized NADPH—hemoprotein reductase] + H2O
(1c) N,N-dihydroxy-L-phenylalanine = (E)-phenylacetaldoxime + CO2 + H2O
Other name(s): phenylalanine N-hydroxylase; CYP79A2 (gene name); CYP79D16 (gene name)
Systematic name: L-phenylalanine,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (N-hydroxylating)
Comments: This cytochrome P-450 (heme-thiolate) enzyme, found in plants, catalyses two successive N-hydroxylations of L-phenylalanine, a committed step in the biosynthesis of benzylglucosinolate and the cyanogenic glucosides (R)-prunasin and (R)-amygdalin. The product of the two hydroxylations, N,N-dihydroxy-L-phenylalanine, is labile and undergoes dehydration followed by decarboxylation, producing an oxime. It is still not known whether the decarboxylation is spontaneous or catalysed by the enzyme.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Wittstock, U. and Halkier, B.A. Cytochrome P450 CYP79A2 from Arabidopsis thaliana L. Catalyzes the conversion of L-phenylalanine to phenylacetaldoxime in the biosynthesis of benzylglucosinolate. J. Biol. Chem. 275 (2000) 14659–14666. [DOI] [PMID: 10799553]
2.  Yamaguchi, T., Yamamoto, K. and Asano, Y. 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. Plant Mol. Biol. 86 (2014) 215–223. [DOI] [PMID: 25015725]
[EC 1.14.14.40 created 2011 as EC 1.14.13.124, transferred 2017 to EC 1.14.14.40]
 
 
EC 1.14.14.44     
Accepted name: phenylacetaldehyde oxime monooxygenase
Reaction: (E)-phenylacetaldehyde oxime + [reduced NADPH—hemoprotein reductase] + O2 = (R)-mandelonitrile + [oxidized NADPH—hemoprotein reductase] + 2 H2O (overall reaction)
(1a) (E)-phenylacetaldehyde oxime = (Z)-phenylacetaldehyde oxime
(1b) (Z)-phenylacetaldehyde oxime = phenylacetonitrile + H2O
(1c) phenylacetonitrile + [reduced NADPH—hemoprotein reductase] + O2 = (R)-mandelonitrile + [oxidized NADPH—hemoprotein reductase] + H2O
Glossary: (R)-mandelonitrile = (2R)-hydroxy(phenyl)acetonitrile
Other name(s): CYP71AN24 (gene name)
Systematic name: (E)-phenylacetaldehyde oxime,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase
Comments: This cytochrome P-450 (heme-thiolate) enzyme is involved in the biosynthesis of the cyanogenic glucosides (R)-prunasin and (R)-amygdalin. It catalyses three different activities - isomerization of the (E) isomer to the (Z) isomer, dehydration, and C-hydroxylation.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Yamaguchi, T., Yamamoto, K. and Asano, Y. 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. Plant Mol. Biol. 86 (2014) 215–223. [DOI] [PMID: 25015725]
[EC 1.14.14.44 created 2017]
 
 
EC 2.4.1.354     
Accepted name: (R)-mandelonitrile β-glucosyltransferase
Reaction: UDP-α-D-glucose + (R)-mandelonitrile = UDP + (R)-prunasin
Glossary: (R)-mandelonitrile = (2R)-hydroxy(phenyl)acetonitrile
(R)-prunasin = (2R)-(β-D-glucosyloxy)(phenyl)acetonitrile
Other name(s): UGT85A19 (gene name)
Systematic name: UDP-α-D-glucose:(R)-mandelonitrile β-D-glucosyltransferase (configuration-inverting)
Comments: The enzyme, characterized from Prunus dulcis (almond), is involved in the biosynthesis of the cyanogenic glycosides (R)-prunasin and (R)-amygdalin.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc
References:
1.  Franks, T. K., Yadollahi, A., Wirthensohn, M. G., Guerin, J. R., Kaiser, B. N., Sedgley, M. and Ford, C. M. A seed coat cyanohydrin glucosyltransferase is associated with bitterness in almond (Prunus dulcis) kernels. Funct. Plant Biol. 35 (2008) 236–246.
[EC 2.4.1.354 created 2018]
 
 
EC 3.2.1.117     
Accepted name: amygdalin β-glucosidase
Reaction: (R)-amygdalin + H2O = (R)-prunasin + D-glucose
Other name(s): amygdalase; amygdalinase; amygdalin hydrolase; amygdalin glucosidase
Systematic name: amygdalin β-D-glucohydrolase
Comments: Highly specific; does not act on prunasin, linamarin, gentiobiose or cellobiose (cf. EC 3.2.1.21 β-glucosidase).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 51683-43-3
References:
1.  Kuroki, G., Lizotte, P.A. and Poulton, J.E. L-β-Glycosidases from Prunus serotina EHRH and Davallia trichomanoides. Z. Natursforsch. C: Biosci. 39 (1984) 232–239.
[EC 3.2.1.117 created 1989]
 
 
EC 3.2.1.118     
Accepted name: prunasin β-glucosidase
Reaction: (R)-prunasin + H2O = D-glucose + mandelonitrile
Other name(s): prunasin hydrolase
Systematic name: prunasin β-D-glucohydrolase
Comments: Highly specific; does not act on amygdalin, linamarin or gentiobiose. (cf. EC 3.2.1.21 β-glucosidase).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 9023-41-0
References:
1.  Kuroki, G., Lizotte, P.A. and Poulton, J.E. L-β-Glycosidases from Prunus serotina EHRH and Davallia trichomanoides. Z. Natursforsch. C: Biosci. 39 (1984) 232–239.
[EC 3.2.1.118 created 1989]
 
 
EC 3.2.1.119     
Accepted name: vicianin β-glucosidase
Reaction: (R)-vicianin + H2O = mandelonitrile + vicianose
Other name(s): vicianin hydrolase
Systematic name: (R)-vicianin β-D-glucohydrolase
Comments: Also hydrolyses, more slowly, (R)-amygdalin and (R)-prunasin, but not gentiobiose, linamarin or cellobiose.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 91608-93-4
References:
1.  Kuroki, G., Lizotte, P.A. and Poulton, J.E. L-β-Glycosidases from Prunus serotina EHRH and Davallia trichomanoides. Z. Natursforsch. C: Biosci. 39 (1984) 232–239.
[EC 3.2.1.119 created 1989]
 
 


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