Abstract
A cinnamoyl esterase, ferulic acid esterase A, from Aspergillus niger releases ferulic acid and 5-5- and 8-O-4-dehydrodiferulic acids from plant cell walls. The breakage of one or both ester bonds from dehydrodimer cross- links between plant cell wall polymers is essential for optimal action of carbohydrases on these substrates, but it is not known if cinnamoyl esterases can break these cross-links by cleaving one of the ester linkages which would not release the free dimer. It is difficult to determine the mechanism of the reaction on complex substrates, and so we have examined the catalytic properties of ferulic acid esterase A from Aspergillus niger using a range of synthetic ethyl esterified dehydrodimers (5-5-, 8-5-benzofuran and 8-O-4-) and two 5-5-diferulate oligosaccharides. Our results show that the esterase is able to cleave the three major dehydrodiferulate crosslinks present in plant cell walls. The enzyme is highly specific at hydrolysing the 5-5- and the 8-5-benzofuran diferulates but the 8-O-4-is a poorer substrate. The hydrolysis of dehydrodiferulates to free acids occurs in two discrete steps, one involving dissociation of a monoesterified intermediate which is negatively charged at the pH of the reaction. Although ferulic acid esterase A was able to release monoesters as products of reactions with all three forms of diesters, only the 5-5- and the 8-O-4-monoesters were substrates for the enzyme, forming the corresponding free diferulic acids. The esterase cannot hydrolyse the second ester bond from the 8-5-benzofuran monoester and therefore, ferulic acid esterase A does not form 8-5-benzofuran diferulic acid. Therefore, ferulic acid esterase A from Aspergillus niger contributes to total plant cell wall degradation by cleaving at least one ester bond from the diferulate cross-links that exist between wall polymers but does not always release the free acid product.
| Original language | English |
|---|---|
| Pages (from-to) | 644-652 |
| Number of pages | 9 |
| Journal | European Journal of Biochemistry |
| Volume | 266 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 1 Dec 1999 |
| Externally published | Yes |
Keywords
- Cross-links
- Dehydrodiferulic acids
- Esterase
- Ferulic acid
- Plant cell walls
Cite this
}
A cinnamoyl esterase from Aspergillus niger can break plant cell wall cross-links without release of free diferulic acids. / Garcia-Conesa, Maria Teresa; Kroon, Paul A.; Ralph, John; Mellon, Fred A.; Colquhoun, Ian J.; Saulnier, Luc; Thibault, Jean François; Williamson, Gary.
In: European Journal of Biochemistry, Vol. 266, No. 2, 01.12.1999, p. 644-652.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - A cinnamoyl esterase from Aspergillus niger can break plant cell wall cross-links without release of free diferulic acids
AU - Garcia-Conesa, Maria Teresa
AU - Kroon, Paul A.
AU - Ralph, John
AU - Mellon, Fred A.
AU - Colquhoun, Ian J.
AU - Saulnier, Luc
AU - Thibault, Jean François
AU - Williamson, Gary
PY - 1999/12/1
Y1 - 1999/12/1
N2 - A cinnamoyl esterase, ferulic acid esterase A, from Aspergillus niger releases ferulic acid and 5-5- and 8-O-4-dehydrodiferulic acids from plant cell walls. The breakage of one or both ester bonds from dehydrodimer cross- links between plant cell wall polymers is essential for optimal action of carbohydrases on these substrates, but it is not known if cinnamoyl esterases can break these cross-links by cleaving one of the ester linkages which would not release the free dimer. It is difficult to determine the mechanism of the reaction on complex substrates, and so we have examined the catalytic properties of ferulic acid esterase A from Aspergillus niger using a range of synthetic ethyl esterified dehydrodimers (5-5-, 8-5-benzofuran and 8-O-4-) and two 5-5-diferulate oligosaccharides. Our results show that the esterase is able to cleave the three major dehydrodiferulate crosslinks present in plant cell walls. The enzyme is highly specific at hydrolysing the 5-5- and the 8-5-benzofuran diferulates but the 8-O-4-is a poorer substrate. The hydrolysis of dehydrodiferulates to free acids occurs in two discrete steps, one involving dissociation of a monoesterified intermediate which is negatively charged at the pH of the reaction. Although ferulic acid esterase A was able to release monoesters as products of reactions with all three forms of diesters, only the 5-5- and the 8-O-4-monoesters were substrates for the enzyme, forming the corresponding free diferulic acids. The esterase cannot hydrolyse the second ester bond from the 8-5-benzofuran monoester and therefore, ferulic acid esterase A does not form 8-5-benzofuran diferulic acid. Therefore, ferulic acid esterase A from Aspergillus niger contributes to total plant cell wall degradation by cleaving at least one ester bond from the diferulate cross-links that exist between wall polymers but does not always release the free acid product.
AB - A cinnamoyl esterase, ferulic acid esterase A, from Aspergillus niger releases ferulic acid and 5-5- and 8-O-4-dehydrodiferulic acids from plant cell walls. The breakage of one or both ester bonds from dehydrodimer cross- links between plant cell wall polymers is essential for optimal action of carbohydrases on these substrates, but it is not known if cinnamoyl esterases can break these cross-links by cleaving one of the ester linkages which would not release the free dimer. It is difficult to determine the mechanism of the reaction on complex substrates, and so we have examined the catalytic properties of ferulic acid esterase A from Aspergillus niger using a range of synthetic ethyl esterified dehydrodimers (5-5-, 8-5-benzofuran and 8-O-4-) and two 5-5-diferulate oligosaccharides. Our results show that the esterase is able to cleave the three major dehydrodiferulate crosslinks present in plant cell walls. The enzyme is highly specific at hydrolysing the 5-5- and the 8-5-benzofuran diferulates but the 8-O-4-is a poorer substrate. The hydrolysis of dehydrodiferulates to free acids occurs in two discrete steps, one involving dissociation of a monoesterified intermediate which is negatively charged at the pH of the reaction. Although ferulic acid esterase A was able to release monoesters as products of reactions with all three forms of diesters, only the 5-5- and the 8-O-4-monoesters were substrates for the enzyme, forming the corresponding free diferulic acids. The esterase cannot hydrolyse the second ester bond from the 8-5-benzofuran monoester and therefore, ferulic acid esterase A does not form 8-5-benzofuran diferulic acid. Therefore, ferulic acid esterase A from Aspergillus niger contributes to total plant cell wall degradation by cleaving at least one ester bond from the diferulate cross-links that exist between wall polymers but does not always release the free acid product.
KW - Cross-links
KW - Dehydrodiferulic acids
KW - Esterase
KW - Ferulic acid
KW - Plant cell walls
UR - http://www.scopus.com/inward/record.url?scp=0033485928&partnerID=8YFLogxK
U2 - 10.1046/j.1432-1327.1999.00910.x
DO - 10.1046/j.1432-1327.1999.00910.x
M3 - Article
VL - 266
SP - 644
EP - 652
JO - European Journal of Biochemistry
JF - European Journal of Biochemistry
SN - 0014-2956
IS - 2
ER -