αβ-Dehydro-3,4-dihydroxyphenylalanine derivatives: Rate and mechanism of formation

Rzepecki, Leszek M.; Waite, J. Herbert

doi:10.1016/0003-9861(91)90324-c

Cited by 48 publications

(49 citation statements)

References 22 publications

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“…There was a nonstoichiometric conversion of quinone to α,β-dehydrodopamine, resulting from competing reactions that may not have detectable absorbance signatures. 57 …”

Section: Results and Discussionmentioning

confidence: 99%

“…Under mildly acidic conditions (pH = 6), quinone tautomerizes to form quinone methide, which further transforms into α,β-dehydrodopamine (reaction 2 ). 57 Although quinone methide is a highly reactive chemical species, Li and Christensen 59 suggested that quinone methide is stabilized under acidic conditions, which likely retarded subsequent reactions. At higher pH (pH = 7–8), quinone transforms directly into α,β-dehydrodopamine involving a charge transfer complex formation with the dopamine catechol (reaction 3 ).…”

Section: Results and Discussionmentioning

confidence: 99%

“…At higher pH (pH = 7–8), quinone transforms directly into α,β-dehydrodopamine involving a charge transfer complex formation with the dopamine catechol (reaction 3 ). 57 This pH-associated difference in the reaction pathway likely contributed to the observed difference in the curing rate of PEG-D. The α,β-dehydrodopamine can be further oxidized to its quinone form through the interaction with dopamine quinone, molecular oxygen, or residual oxidant (e.g., NaIO 3 ; reaction 4 ).…”

Section: Results and Discussionmentioning

confidence: 99%

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Effect of pH on the Rate of Curing and Bioadhesive Properties of Dopamine Functionalized Poly(ethylene glycol) Hydrogels

et al. 2014

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The remarkable underwater adhesion strategy employed by mussels has inspired bioadhesives that have demonstrated promise in connective tissue repair, wound closure, and local delivery of therapeutic cells and drugs. While the pH of oxygenated blood and internal tissues is typically around 7.4, skin and tumor tissues are significantly more acidic. Additionally, blood loss during surgery and ischemia can lead to dysoxia, which lowers pH levels of internal tissues and organs. Using 4-armed PEG end-capped with dopamine (PEG-D) as a model adhesive polymer, the effect of pH on the rate of intermolecular cross-linking and adhesion to biological substrates of catechol-containing adhesives was determined. Adhesive formulated at an acidic pH (pH 5.7–6.7) demonstrated reduced curing rate, mechanical properties, and adhesive performance to pericardium tissues. Although a faster curing rate was observed at pH 8, these adhesives also demonstrated reduced mechanical and bioadhesive properties when compared to adhesives buffered at pH 7.4. Adhesives formulated at pH 7.4 demonstrated a good balance of fast curing rate, elevated mechanical properties and interfacial binding ability. UV–vis spectroscopy evaluation revealed that the stability of the transient oxidation intermediate of dopamine was increased under acidic conditions, which likely reduced the rate of intermolecular cross-linking and bulk cohesive properties for hydrogels formulated at these pH levels. At pH 8, competing cross-linking reaction mechanisms and reduced concentration of dopamine catechol due to auto-oxidation likely reduced the degree of dopamine polymerization and adhesive strength for these hydrogels. pH plays an important role in the adhesive performance of mussel-inspired bioadhesives and the pH of the adhesive formulation needs to be adjusted for the intended application.

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“…There was a nonstoichiometric conversion of quinone to α,β-dehydrodopamine, resulting from competing reactions that may not have detectable absorbance signatures. 57 …”

Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

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Effect of pH on the Rate of Curing and Bioadhesive Properties of Dopamine Functionalized Poly(ethylene glycol) Hydrogels

et al. 2014

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“…The cohesive energy of the films was not completely abolished suggesting that some of the Dopa in the mfp-3f film was shielded from oxidation or based upon an adhesion independent of Dopa. The long range-repulsion has been attributed to the increased thickness of the protein films due to the stiffening of the mfp-3 backbone caused by quinone tautomerization to dehydroDopa [19]. On reducing the pH back to pH 3.0, the cohesion between the oxidized mfp-3 films increased significantly to W c = 4.1 ± 0.1 mJ/m 2 and W c = 5.7 mJ/m 2 for short and long contact times, respectively.…”

Section: Resultsmentioning

confidence: 99%

Mussel adhesive protein provides cohesive matrix for collagen type-1α

et al. 2015

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Understanding the interactions between collagen and adhesive mussel foot proteins (mfps) can lead to improved medical and dental adhesives, particularly for collagen-rich tissues. Here we investigated interactions between collagen type-1, the most abundant loadbearing animal protein, and mussel foot protein-3 (mfp-3) using a quartz crystal microbalance and surface forces apparatus (SFA). Both hydrophilic and hydrophobic variants of mfp-3 were exploited to probe the nature of the interaction between the protein and collagen. Our chief findings are: 1) mfp-3 is an effective chaperone for tropocollagen adsorption to TiO2 and mica surfaces; 2) at pH 3, collagen addition between two mfp-3 films (Wc = 5.4 ± 0.2 mJ/m2) increased their cohesion by nearly 35%; 3) oxidation of Dopa in mfp-3 by periodate did not abolish the adhesion between collagen and mfp-3 films, and 4) collagen bridging between both hydrophilic and hydrophobic mfp-3 variant films is equally robust, suggesting that hydrophobic interactions play a minor role. Extensive H-bonding, π-cation and electrostatic interactions are more plausible to explain the reversible bridging of mfp-3 films by collagen.

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“…Quinone tautomers such as dehydro-Dopa and dehydro-Dopa-quinone methide B are equally or more likely products at pH 7–8 and were hypothesized previously. 13,14 Do these products have a bearing on adhesion? According to QCM results, the level of adsorption of Δ D to TiO 2 is 20 times greater than that of D .…”

Section: Discussionmentioning

confidence: 99%

α,β-Dehydro-Dopa: A Hidden Participant in Mussel Adhesion

et al. 2016

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Dopa (L-3,4-dihydroxyphenylalanine) is a key chemical signature of mussel adhesive proteins, but its susceptibility to oxidation has limited mechanistic investigations as well as practical translation to wet adhesion technology. To investigate peptidyl-Dopa oxidation, the highly diverse chemical environment of Dopa in mussel adhesive proteins was simplified to a peptidyl-Dopa analogue, N-acetyl-Dopa ethyl ester. On the basis of cyclic voltammetry and UV–vis spectroscopy, the Dopa oxidation product at neutral to alkaline pH was shown to be α,β-dehydro-Dopa (ΔD), a vinylcatecholic tautomer of Dopa-quinone. ΔD exhibited an adsorption capacity on TiO2 20-fold higher than that of the Dopa homologue in the quartz crystal microbalance. Cyclic voltammetry confirmed the spontaneity of ΔD formation in mussel foot protein 3F at neutral pH that is coupled to a change in protein secondary structure from random coil to β-sheet. A more complete characterization of ΔD reactivity adds a significant new perspective to mussel adhesive chemistry and the design of synthetic bioinspired adhesives.

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αβ-Dehydro-3,4-dihydroxyphenylalanine derivatives: Rate and mechanism of formation

Cited by 48 publications

References 22 publications

Effect of pH on the Rate of Curing and Bioadhesive Properties of Dopamine Functionalized Poly(ethylene glycol) Hydrogels

Effect of pH on the Rate of Curing and Bioadhesive Properties of Dopamine Functionalized Poly(ethylene glycol) Hydrogels

Mussel adhesive protein provides cohesive matrix for collagen type-1α

α,β-Dehydro-Dopa: A Hidden Participant in Mussel Adhesion

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