Crosslinking of Fibrous Proteins by Formaldehyde

Mason, P.; Griffith, June C.

doi:10.1038/203484a0

Cited by 20 publications

(5 citation statements)

References 7 publications

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“…The comparative data in Figure 6 show that the formaldehyde and I3enax treatments elevate the transition temperature for 57c extension by about 10° C. Such an effect might 1>e expected for the formaldehyde treatment, because it has been shown [17] to be capable of cross-linking both the matrix proteins and the main helix-forming proteins in wool; cross-linking the oriented molecules in a fibrous polymer tends to elevate the transition temperature. and increases from 10° C to 20° C are commonly obtained for the collagen/water system using different cross-linking agents.…”

Section: Discussionmentioning

confidence: 85%

Thermal Transitions in Keratin

Mason

1965

Textile Research Journal

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Wool fibers in water at room temperature were extended by constant loads chosen to produce extensions in the range 0% to 25%. After relaxation for 1 hr, the temperature was increased to 100° C at a constant rate of approximately 1° C/min. The length of the specimens increased progressively with the temperature; the increase was taken as a measure of a transformation in the fibers, which embodies both the normal α ⇄ β phase transition of α-helical proteins as well as other structural changes which may contribute to the free energy of the transition in keratin. On reduction of the temperature from a higher to lower value, there was generally no recovery of length, although in comparable experiments at constant extension there was a considerable recovery of the force.Under the present conditions, it was not possible to observe the length changes corresponding to the complete transformation. However, families of curves for arbitrary small extensions were obtained for different stresses and used to calculate "effective" thermodynamic parameters appropriate to the time scale of the experiments. The entropy of transition was found to be 6 cal/deg mole of residues, and the heat of transition was 3 kcal/mole of residues. Treatment by formaldehyde or by an anionic detergent appeared to elevate the temperature range of the transition region, whereas permanently setting the fiber or testing at pH 1 depressed it. Measurements on unmodified wool fibers in water at different temperatures indicated the existence of a viscous flow mechanism with an apparent activation energy of 28 kcal/mole.

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Section: Discussionmentioning

confidence: 85%

Thermal Transitions in Keratin

Mason

1965

Textile Research Journal

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“…This value can be compared with the 30% increase for HCHOtreated fibers measured in HCOOH and provides evidence for cross-linking by HCHO, which is independent of crystallinity within the fiber during measurement. The stiffening of the control fibers caused by the water treatment contrasts with the slight softening observed when such fibers were measured in formic acid [7]. LiBr by about 34% (38% for an untreated fiber).…”

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confidence: 68%

“…The solid line in Figure 1 shows the predicted line given by Equation 5, while In a previous paper [7], we proposed that the formation of cross links by formaldehyde (HCHO) in fibrous proteins such as wool can be demonstrated by the increased modulus of the fiber in 98% formic acid (HCOOH) after HCHO treatment. The initial modulus of a wool fiber in HCOOH is' about 7 X lOR dynes/cm'= or about one-twentieth of its value in water.…”

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confidence: 91%

“…The mean modulus of this wpol (15 fibers) in LiBr, based on the wet, unconstrained length and cross-sectional area of the fiber,was 1.5 X 10~ dyneS/CM2. The LiBr was then washed oiat of the fiber with distilled water, the fiber treated with 36% w/v aqueous HCHO solution at pH 3 for 14 hr at 52*C, as previously described [7], and the modulus in 6 M LiBr at 25°C was again determined. Control experiments were performed by treating the contracted fibers with water for 24 hr at 52°C instead of HCHO solution.…”

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confidence: 99%

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The Effect of Formaldehyde on Wool Before, During and After Contraction in Lithium Bromide Solution

Griffith

Mason

1966

Textile Research Journal

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“…It is now well known that the treatment of wool with formaldehyde introduces cross links [1,6,8,9,10,12,13]. Formaldehyde treatment of set fabrics might, therefore, be expected to stabilize set by introducing cross links between the polypeptide chains in their new conformation.…”

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confidence: 99%