Action of Aromatic Isocyanates on Proteins

Fraenkel‐Conrat, H.; Cooper, Mitzi; Olcott, Henry Steel

doi:10.1021/ja01218a049

Cited by 30 publications

(16 citation statements)

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“…Presumably all side chains with reactive hydrogen atoms, namely, amino, hydroxyl, thiol, phenolic, amide, guanidino, and imidazoyl groups, are capable of reacting with isocyanates [3,4]. The free carboxyl groups also form mixed anhydrides [4] ; however, these are known to decompose, either spontaneously or at elevated temperatures [2] and are likely to undergo some change when the wool is dried at 105 ° C. prior to determining dry weights. The conversion of polar functional groups to less polar side chains may contribute to stabilizing the wool toward acid.…”

Section: Discussionmentioning

confidence: 99%

“…Spindle hours totaled about 12,000 per cotton. [4] in this laboratory showed that reaction of several proteins with aromatic isocyanates is extensive in anhydrous pyridine at elevated temperatures. More recently Farnworth [3] noted that similar treatment of wool with phenyl isocyanate increases the stability toward degradation by acids, alkalies, and reducing agents.…”

Section: Spinning Testmentioning

confidence: 99%

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Modification of Wool with Monofunctional Isocyanates

Moore

1956

Textile Research Journal

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936 each cotton so that from these, equal weights of combed sliver would result with 12%, 16%, and 20% noil removal.A Saco-Lowell comber was used at a speed of 101 nips per minute to obtain a 112-grain combed sliver with the various noil removals. Finisher drawing consisted of two processes with six doublings in each to produce 60-grain sliver. The first was on a 5-roll Saco-Lowell frame, the second on a Medley 4-roll draw frame.For the roving operation each cotton-noils combination was divided in two for making 2-hank and 4-hank roving, respectively. The 2-hank was made on an H and B Whitin CID roving frame with 4-roll drawing. Twenty-four spindles were used, four for each cotton-noils combination. Halfway through processing spindles for the Rainmed and Irrmed samples were interchanged. A similar procedure was used with the 4-hank roving process which was carried out on a 4-roll H and B Whitin CSD frame with Casablanca system. Spinning TestTwo Whitin long draft, Casablanca system, spinning frames in the regular production area were used in the spinning test. One was assigned to spin double roving (4-hank), and the other was assigned to spin single roving (2-hank). The Rainmed and Irrmed cottons were spun on opposite sides and reversed halfway through processing. Rovings of different combing levels were grouped separately on the frames.Spinning was conducted on a 3-shift basis for three successive days and was under constant supervision by laboratory personnel. The same checkers and spinners were used throughout the test. Spindle hours totaled about 12,000 per cotton. AbstractThe reaction of wool with ethyl, octadecyl, phenyl, and α-naphthyl isocyanates under anhydrous conditions is described. At low uptakes these reagents confer marked resistance toward solubilization in hot acid; increasing uptakes reduce the felting shrinkage and impart stability to degradation by alkali and oxidizing and reducing agents.

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Section: Discussionmentioning

confidence: 99%

Section: Spinning Testmentioning

confidence: 99%

Modification of Wool with Monofunctional Isocyanates

Moore

1956

Textile Research Journal

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“…The latter were calculated on the basis of the assumption that isocyanates react completely with basic and hydroxyl amino acid residues of keratins, 6,13 whose concentration accounts for about 0.28 mmol/g (carboxyl groups may react as well, but at a much lower rate). 13,14 Aliphatic isocyanates displayed higher reactivity than aromatic ones, regardless of the presence of one or two cyanate groups. HMD reached about 70% of the theoretical saturation value.…”

Section: Chemical Reactivitymentioning

confidence: 99%

Physical properties of wool fibers modified with isocyanate compounds

Freddi¹,

Innocenti

Arai

et al. 2003

J of Applied Polymer Sci

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Wool fibers were chemically modified with various kinds of isocyanates and diisocyanates. The reactivity of these modifying agents was examined as a function of the reaction solvent, temperature, time, and isocyanate chemistry. The use of dimethyl sulfoxide as the solvent, aliphatic mono and bifunctional isocyanates, such as dodecyl isocyanates and hexamethylene diisocyanate, and a temperature of 75°C resulted in higher weight gains. The moisture content of wool fibers tended to decrease with increasing the weight gain, the extent of which depended on the isocyanate used. Monofunctional isocyanates caused a sharp drop of tensile strength and an increase of elongation at break, while bifunctional isocyanates preserved the intrinsic tensile properties of wool. The FTIR spectra showed changes in the amide I, II, and III ranges, in the CO stretching range at 1750 -1700 cm Ϫ1 , and in the CH stretching and bending regions at 3000 -2800 and 1500 -1350 cm Ϫ1, respectively, attributable to the incorporation of the modifying agent. DSC measurements highlighted remarkable changes in the thermal behavior of acylated wool fibers. The bimodal melting endotherm at 230 -240°C shifted to lower temperature, and the relative intensity of the constituent peaks changed as a function of the weight gain. Foreign deposits adhering to the surface of chemically modified wool fibers were detected by SEM analysis.

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“…The effect of a longchain hydrocarbon salt on egg albumin in which basic groups had been blocked with phenyl isocyanate has also been examined. When treated with phenyl isocyanate by a method developed by Fraenkel-Conrat and others in the Western Regional Research Laboratory [20], egg albumin is insoluble. After standing in contact with a 5-percent aqueous solution of alkylbenzene sulfonate for two weeks and then being washed with water, the treated egg albumin had the same nitrogen content as before the treatment ; thus it appears that no significant combination occurred between the treated protein and the detergent.…”

Section: Denaturation and Unfolding Of Proteinsmentioning

confidence: 99%