Enzymes
UniProtKB help_outline | 3 proteins |
Enzyme class help_outline |
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GO Molecular Function help_outline |
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Reaction participants Show >> << Hide
- Name help_outline (R)-prunasin Identifier CHEBI:17396 (Beilstein: 91509; CAS: 99-18-3) help_outline Charge 0 Formula C14H17NO6 InChIKeyhelp_outline ZKSZEJFBGODIJW-GMDXDWKASA-N SMILEShelp_outline OC[C@H]1O[C@@H](O[C@@H](C#N)c2ccccc2)[C@H](O)[C@@H](O)[C@@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 3 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2O Identifier CHEBI:15377 (Beilstein: 3587155; CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,048 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline D-glucose Identifier CHEBI:4167 (Beilstein: 1281604; CAS: 2280-44-6) help_outline Charge 0 Formula C6H12O6 InChIKeyhelp_outline WQZGKKKJIJFFOK-GASJEMHNSA-N SMILEShelp_outline OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 152 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline mandelonitrile Identifier CHEBI:16910 (Beilstein: 2207122; CAS: 532-28-5) help_outline Charge 0 Formula C8H7NO InChIKeyhelp_outline NNICRUQPODTGRU-UHFFFAOYSA-N SMILEShelp_outline OC(C#N)c1ccccc1 2D coordinates Mol file for the small molecule Search links Involved in 8 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:16489 | RHEA:16490 | RHEA:16491 | RHEA:16492 | |
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Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Isolation and characterization of multiple forms of prunasin hydrolase from black cherry (Prunus serotina Ehrh.) seeds.
Kuroki G.W., Poulton J.E.
Three forms of prunasin hydrolase (PH I, PH IIa, and PH IIb), which catalyze the hydrolysis of (R)-prunasin to mandelonitrile and D-glucose, have been purified from homogenates of mature black cherry (Prunus serotina Ehrh.) seeds. Hydroxyapatite chromatography completely resolved PH I from PH IIa ... >> More
Three forms of prunasin hydrolase (PH I, PH IIa, and PH IIb), which catalyze the hydrolysis of (R)-prunasin to mandelonitrile and D-glucose, have been purified from homogenates of mature black cherry (Prunus serotina Ehrh.) seeds. Hydroxyapatite chromatography completely resolved PH I from PH IIa and PH IIb. PH IIa and IIb, which coeluted on hydroxyapatite, were resolved by gel filtration. PH IIa was a dimer with a native molecular weight of 140,000. Both PH I and PH IIb were monomeric with molecular weights of 68,000. The isozymes appeared to be glycoproteins based on their binding to concanavalin A-Sepharose 4B with subsequent elution by alpha-methyl-D-glucoside. When presented several potential glycosidic substrates, these enzymes exhibited a narrow specificity towards (R)-prunasin. Km values for (R)-prunasin for PH I, PH IIa, and PH IIb were 1.73, 2.3, and 1.35 mM, respectively. PH I and PH IIb possessed fivefold greater Vmax/Km values than PH IIa. Ortho- and para-nitrophenyl-beta-D-glucosides were hydrolyzed at the same active site. All forms had a pH optimum of 5.0 in citrate-phosphate buffer. PH I and PH IIb were competitively inhibited by castanospermine with Ki values of 0.19 and 0.09 mM, respectively. PH activity was not stimulated by any metal ion tested and was unaffected by diethyldithiocarbamate, o-phenanthroline, 2,2'-dipyridyl, and EDTA. << Less
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Amygdalin degradation by Mucor circinelloides and Penicillium aurantiogriseum: mechanisms of hydrolysis.
Brimer L., Cicalini A.R., Federici F., Petruccioli M.
Mucor circinelloides LU M40 and Penicillium aurantiogriseum P 35 produce extracellular beta-glycosidases that are active on the cyanogenic glycoside amygdalin. From the culture broths of M. circinelloides, only one beta-glycosidase could be identified, while two different enzymes - both having amy ... >> More
Mucor circinelloides LU M40 and Penicillium aurantiogriseum P 35 produce extracellular beta-glycosidases that are active on the cyanogenic glycoside amygdalin. From the culture broths of M. circinelloides, only one beta-glycosidase could be identified, while two different enzymes - both having amygdalase activity - were found in culture broths of P. aurantiogriseum. The study of the mechanism of hydrolysis of the beta-bis-glycoside amygdalin with purified enzymes from the two organisms indicated a possible sequential (two-step) reaction. In all cases, the first step of hydrolysis from amygdalin to prunasin was very rapid, while the second step from prunasin to cyanohydrin was much slower. No cyanohydrin lyase activity was found in the culture broths of either fungus. << Less
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Investigation of the microheterogeneity and aglycone specificity-conferring residues of black cherry prunasin hydrolases.
Zhou J., Hartmann S., Shepherd B.K., Poulton J.E.
In black cherry (Prunus serotina Ehrh.) seed homogenates, (R)-amygdalin is degraded to HCN, benzaldehyde, and glucose by the sequential action of amygdalin hydrolase (AH), prunasin hydrolase (PH), and mandelonitrile lyase. Leaves are also highly cyanogenic because they possess (R)-prunasin, PH, an ... >> More
In black cherry (Prunus serotina Ehrh.) seed homogenates, (R)-amygdalin is degraded to HCN, benzaldehyde, and glucose by the sequential action of amygdalin hydrolase (AH), prunasin hydrolase (PH), and mandelonitrile lyase. Leaves are also highly cyanogenic because they possess (R)-prunasin, PH, and mandelonitrile lyase. Taking both enzymological and molecular approaches, we demonstrate here that black cherry PH is encoded by a putative multigene family of at least five members. Their respective cDNAs (designated Ph1, Ph2, Ph3, Ph4, and Ph5) predict isoforms that share 49% to 92% amino acid identity with members of glycoside hydrolase family 1, including their catalytic asparagine-glutamate-proline and isoleucine-threonine-glutamate-asparagine-glycine motifs. Furthermore, consistent with the vacuolar/protein body location and glycoprotein character of these hydrolases, their open reading frames predict N-terminal signal sequences and multiple potential N-glycosylation sites. Genomic sequences corresponding to the open reading frames of these PHs and of the previously isolated AH1 isoform are interrupted at identical positions by 12 introns. Earlier studies established that native AH and PH display strict specificities toward their respective glucosidic substrates. Such behavior was also shown by recombinant AH1, PH2, and PH4 proteins after expression in Pichia pastoris. Three amino acid moieties that may play a role in conferring such aglycone specificities were predicted by structural modeling and comparative sequence analysis and tested by introducing single and multiple mutations into isoform AH1 by site-directed mutagenesis. The double mutant AH ID (Y200I and G394D) hydrolyzed prunasin at approximately 150% of the rate of amygdalin hydrolysis, whereas the other mutations failed to engender PH activity. << Less
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Prunus serotina amygdalin hydrolase and prunasin hydrolase: purification, N-terminal sequencing, and antibody production.
Li C.P., Swain E., Poulton J.E.
In black cherry (Prunus serotina Ehrh.) seed homogenates, amygdalin hydrolase (AH) participates with prunasin hydrolase (PH) and mandelonitrile lyase in the sequential degradation of (R)-amygdalin to HCN, benzaldehyde, and glucose. Four isozymes of AH (designated AH I, I', II, II') were purified f ... >> More
In black cherry (Prunus serotina Ehrh.) seed homogenates, amygdalin hydrolase (AH) participates with prunasin hydrolase (PH) and mandelonitrile lyase in the sequential degradation of (R)-amygdalin to HCN, benzaldehyde, and glucose. Four isozymes of AH (designated AH I, I', II, II') were purified from mature cherry seeds by concanavalin A-Sepharose 4B chromatography, ion-exchange chromatography, and chromatofocusing. All isozymes were monomeric glycoproteins with native molecular masses of 52 kD. They showed similar kinetic properties (pH optima, K(m), V(max)) but differed in their isoelectric points and N-terminal amino acid sequences. Analytical isoelectric focusing revealed the presence of subisozymes of each isozyme. The relative abundance of these isozymes and/or subisozymes varied from seed to seed. Three isozymes of PH (designated PH I, IIa, and IIb) were purified to apparent homogeneity by affinity, ion-exchange, and hydroxyapatite chromatography and by nondenaturing polyacrylamide gel electrophoresis. PH I and PH IIb are 68-kD monomeric glycoproteins, whereas PH IIa is dimeric (140 kD). The N-terminal sequences of all PH and AH isozymes showed considerable similarity. Polyclonal antisera raised in rabbits against deglycosylated AH I or a mixture of the three deglycosylated PH isozymes were not monospecific as judged by immunoblotting analysis, but also cross-reacted with the opposing glucosidase. Monospecific antisera deemed suitable for immunocytochemistry and screening of expression libraries were obtained by affinity chromatography. Each antiserum recognized all known isozymes of the specific glucosidase used as antigen. << Less
Plant Physiol. 100:282-290(1992) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.