The Enhanced Esterolytic Catalysis of Poly-4 (5)-vinylimidazole and Poly-5 (6)-vinylbenzimidazole<sup>1</sup>

Overberger, C. G.; Pierre, Thomas St.; Vorchheimer, N.; Lee, J.; Yaroslavsky, S.

doi:10.1021/ja01080a028

Cited by 116 publications

(30 citation statements)

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“…Compounds 2b-g were prepared by published procedures and had mp in satisfactory agreement with the literature values (35)(36)(37)(38). 2h was prepared by reaction of 2d with CH2N2 in diethyl ether, and recrystallized from petroleum ether: mp 72-73.5 "C. Anal.…”

Section: Substratessupporting

confidence: 60%

A catalyst for ester hydrolysis showing electrostatic and hydrophobic binding properties

Guthrie¹,

Ueda²

1976

Can. J. Chem.

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. Can. J. Chem. 54, 2745Chem. 54, (1976. The steroid 17p-(4-imidazoly1)-5~~-androstane-3p,l lp-diamine, l a , R = H , acts as a catalyst for the hydrolysis of aryl esters. For a series of aryl acetates, 2a-/I, at 1 M ionic strength, log kz for l a catalyzed hydrolysis is linearly related to log kz for imidazole catalyzed hydrolysis, with only 2d, 4-acetoxy-3-nitrobenzoate, deviating: at zero ionic strength, all anionic substrates show positive deviations, and a cationic substrate shows a negative deviation. This is interpreted in terms of a stringent geometrical requirement for strong electrostatic catalysis. With favorable geometry, a 1 :1 electrostatic attraction can lead to a 15 fold rate enhancement ( r = 0). For a series of arylpropionate esters 3a-c, rate constants for l a catalyzed hydrolysis show a small but progressive increase with increasing size of the aryl group: after correcting for substrate reactivity and electrostatic interactions, this hydrophobic effect is independent of the leaving group. l b (R = isopropyl) was prepared to determine the rate of reaction at N-3 of the steroidal imidazole ring: this is the more hindered nitrogen but also the more suitable for hydrophobic binding. l b was markedly less reactive than l a , but showed larger hydrophobic effects. Detailed analysis suggests that the potential hydrophobic rate enhancement for the interaction of a phenanthryl group with the lower surface of a steroid is about 160-fold. This study provides guidelines for the design of enzyme models of greater catalytic efficiency.

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Section: Substratessupporting

confidence: 60%

A catalyst for ester hydrolysis showing electrostatic and hydrophobic binding properties

Guthrie¹,

Ueda²

1976

Can. J. Chem.

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“…A cooperative effect of two interacting catalytic groups, which we invoked to explain the high catalytic efficiency of gels carrying nucleophilic substituents, has been demonstrated on a dissolved catalytic polymer by Overberger et al 29. A similar mechanism may also have been operative in the study of Kiefer et al6, who reported that imidazole residues appended to polyethylene imine which also carried hydrophobic substituents were 1012 times more efficient in catalysing the hydrolysis ef 4-nitrocatechol sulphate than free imidazole.…”

mentioning

confidence: 57%

Kinetics of Intramolecular and Intermolecular Reactions Involving Two Functional Groups Attached to Polymers

MORAWETZ¹

1974

Macromolecular Microsymposia–XII and XIII

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Three types of investigations are described. (a) When a polymer chain carries reactive substituents, the reaction rate may be increased by very large factors if these groups are sufficiently close to each other. More distant groups interact at rates governed by the chain flexibility. A technique is described for studying the effect of the excluded volume on the probability of cyclic chain conformations. (b) When reactive and catalytic substituents are attached to different polymer chains, their reaction should be hindered by the resistance of polymer coils to mutual interpenetration in good solvent media. Two theoretical approaches to this 'kinetic excluded volume effect' are described. Experimental data do not conform to the expected behaviour and the reason for this discrepancy is unknown (c) Crosslinked polyacrylamide beads carrying nucleo philic substituents were evaluated as catalysts for the solvolysis of nitrophenyl esters in a solution phase. Under certain conditions, groups attached to the gel were i uch more efficient catalysts than their analogues in homogeneous solution. This effect was ascribed to a cooperative action of two catalytic groups.

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“…29,30 In the case of proteases, the amideforming reaction is either a thermodynamically or a kinetically controlled process. The latter reaction is more selective in that the enzyme needs to react with an ester compound to form an acylenzyme intermediate.…”

Section: Poly(amino Acid) As An Eco-friendly Materialsmentioning

confidence: 99%

“…75 Contrary to amyloid fibrils, silk β-sheets composed of Gly and Ala did not express significant cytotoxicity, most likely because of a lack of electrical charge. Nano-assembly of silk β-sheets produced microfibrils after incubation for 72 h (Figure 5a), and formation of the nano-assembly was faster than that of Aβ (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28), Aβ (28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42) and full-length Aβ(1-42) because of the greater hydrophobicity of the silk β-sheet. 76,77 The control of silk β-sheet formation is key the assembly needed to create artificial tough polymeric materials; however, this control has not yet been established because β-sheets assemble via hydrophobic interactions too quickly to regulate in solution.…”

Section: Poly(amino Acid)/polypeptide As Structural Materials: Crystamentioning

confidence: 99%

Poly(amino acid)s/polypeptides as potential functional and structural materials

Numata

2015

Polym J

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Poly(amino acids) and polypeptides have the potential to contribute significantly to a biomass-based and sustainable society, due to their biomass origin, functionality, and unique physical properties. To realize amino acid-based polymers as eco-friendly alternatives for petroleum materials, the synthesis of poly(amino acid)s/polypeptides through an environmentally friendly process is needed. In this focus review, the author summarizes the recent progress of chemo-enzymatic polymerization, which is a green and atom-economical reaction that provides new insight into the design of materials from polypeptides. Additionally, polypeptides can be designed to serve as functional and structural materials. The use of peptides as carriers of nucleic acids for delivery into target cells and organelles is one important application of such functional materials. Studies on polypeptides as structural materials are also reviewed. POLY(AMINO ACID) AS AN ECO-FRIENDLY MATERIALEco-friendly polymeric materials have been designed and processed primarily from bio-based polyesters such as poly(hydroxyalkanoate) 1 and poly(lactic acid), 2,3 due to their plasticity, excellent workability, and biomass origin. 4-12 Poly(hydroxyalkanoate) has several advantages such as the ability to be directly synthesized from various types of biomass, including lignin and carbon dioxide, 13-17 and excellent biodegradability. 18,19 However, because of a lack of toughness, this biopolyester has limited use and application. Development of an engineered biopolymer such as a biomass-derived polyamide is an emerging interest in the field of sustainable chemistry and materials engineering. Biopolyamides (for example, nylon 4) have been investigated as candidates for biomass-based engineering plastics, but their narrow processing window for thermo-forming currently prevents them from being considered for practical purposes. 20 Natural high-performance materials, including spider silk and mussel-derived adhesive (Figure 1), are mainly composed of poly(amino acid)s and a small amount of short peptides, suggesting that poly(amino acid)s could serve as an alternative to the petroleum-derived polymers in support of a sustainable society. Although spider dragline silk is a benchmark in terms of tough materials, scientific and technological advances still cannot produce an artificial dragline silk. To create and develop biomass-based tough polymers like this silk, the synthesis and design of materials from poly(amino acid)s is being investigated.A poly(amino acid) is a polymer composed of amino acids as monomeric units. Structural and functional proteins, polypeptides, peptides and polymers derived from amino acids, that is, poly(β-alanine) and ε-poly(lysine), are classified as poly(amino acid)s. The use of poly(amino acid)s as functional materials has been widely studied, resulting in the development of polypeptides that are bioactive and that can have biological applications such as in tissue engineering, regenerative medicine and drug/gene delivery systems. Poly(amin...

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The Enhanced Esterolytic Catalysis of Poly-4 (5)-vinylimidazole and Poly-5 (6)-vinylbenzimidazole¹

Cited by 116 publications

References 0 publications

A catalyst for ester hydrolysis showing electrostatic and hydrophobic binding properties

A catalyst for ester hydrolysis showing electrostatic and hydrophobic binding properties

Kinetics of Intramolecular and Intermolecular Reactions Involving Two Functional Groups Attached to Polymers

Poly(amino acid)s/polypeptides as potential functional and structural materials

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The Enhanced Esterolytic Catalysis of Poly-4 (5)-vinylimidazole and Poly-5 (6)-vinylbenzimidazole1

Cited by 116 publications

References 0 publications

A catalyst for ester hydrolysis showing electrostatic and hydrophobic binding properties

A catalyst for ester hydrolysis showing electrostatic and hydrophobic binding properties

Kinetics of Intramolecular and Intermolecular Reactions Involving Two Functional Groups Attached to Polymers

Poly(amino acid)s/polypeptides as potential functional and structural materials

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Product

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The Enhanced Esterolytic Catalysis of Poly-4 (5)-vinylimidazole and Poly-5 (6)-vinylbenzimidazole¹