N-Acetyl Groups in Wool and Extracted Wool Proteins

O'donnell, IJ; Thompson, Eop; Inglis, AS

doi:10.1071/bi9620732

Cited by 24 publications

(22 citation statements)

References 12 publications

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“…More recently Brown et al (1961) have reported that 8M urea or exposure to pH 10·5 will disaggregate the protein complex procarboxypeptidase into three discrete protein subunits each approximately onethird in size of the procarboxypeptidase and possessing distinct biological activities. We have previously reported Thompson and O'Donnell 1962) that chromatography oflow-sulphur wool proteins on DEAE-cellulose in buffers containing 8M urea leads to resolution of components which show differences in amino acid compositions consistent with the presence of X-keratose in the more strongly bound fractions. Thus the more acidic fraction is richer in cysteic acid, proline, glycine, serine, and tyrosine and lower in lysine and alanine, characteristics of the composition of X-keratose.…”

Section: Disoussionmentioning

confidence: 99%

“…Horner (1954) has reported that hydrolysis of amide bonds in wool does not occur readily at pH 13·3 at 25°C. The simplest explanation for the increase in ninhydrin colour given by these proteins at pH values above approximately pH 10·5 is that there is breakage of peptide bonds although we cannot definitely exclude the possibility that there is a release of additional ninhydrin-reacting groups due to unfolding or disaggregation, or hydrolysis of N-acetyl residues (O'Donnell, Thompson, and Inglis 1962).…”

Section: (E) Effect Of High Ph On the Breakage Of Peptide Bondsmentioning

confidence: 99%

“…Each was finally dialysed against distilled water before freeze-drying. .Samples of freeze-dried protein were hydrolysed for amino acid analysis as described previously (Thompson and O'Donnell 1962). Analyses were made with a Beckman-Spinco analyser according to the method of Spackman, Stein, and Moore (1958).…”

Section: (D) Preparation Of Fractions For Amino Acid Analysismentioning

confidence: 99%

“…Under these conditions 69% (additional to the 6% lost in the washings) of the original wool was extracted. The low-sulphur S-carboxymethyl kerateine A (SCMKA) watj prepared as previously described (O'Donnell, Thompson, and Inglis 1962).…”

Section: (E) Preparation Of S-carboxymethyl Wool Proteinsmentioning

confidence: 99%

“…In a previous paper (Thompson and O'Donnell 1962) it was shown by the technique of peptide-mapping that fractions from IX-keratose, separated by chromatography on DEAE-cellulose in buffers containing 8M urea, were very similar in amino acid sequence despite some marked differences among them in amino acid composition. It was considered that the marked differences between the fractions may be due to a contaminant protein bound to a single IX-keratose protein or to a family of very similar proteins and containing amounts of certain amino acids characteristic of the high-sulphur proteins in wool, e.g.…”

Section: Introductionmentioning

confidence: 99%

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Studies on Oxidized Wool VI. Interactions Between High- and Low-'Sulphur Proteins and their Significance in the Purification of Extracted Wool Proteins

O'donnel¹,

Thompson²

1962

Aust. Jnl. Of Bio. Sci.

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SummaryThe amounts of protein extractable from wool following oxidation with performic acid, and the yields of high. sulphur (y·keratose) and low· sulphur (",-keratose) fractions have been shown to depend markedly on the conditions of dialysis used to remove excess performic acid reagent. The results are explained by assuming that denaturation occurs in warm dilute formic acid. Following denaturation in this way, or following exposure to solutions of trichloroacetic acid or to alkali at pH 11, the extracted proteins are more readily separated into high. and low· sulphur fractions. It is postulated that contaminant high. sulphur protein is responsible, in part, for the chromatographic heterogeneity and for the variation in amino acid composition of separated low· sulphur proteins. Binding of this high· sulphur contaminant protein fraction to the low·sulphur proteins is shown to be by secondary valence bonds. The percentage of high. sulphur proteins in wool is higher than the estimates of earlier workers.

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Section: Disoussionmentioning

confidence: 99%

Section: (E) Effect Of High Ph On the Breakage Of Peptide Bondsmentioning

confidence: 99%

Section: (D) Preparation Of Fractions For Amino Acid Analysismentioning

confidence: 99%

Section: (E) Preparation Of S-carboxymethyl Wool Proteinsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Studies on Oxidized Wool VI. Interactions Between High- and Low-'Sulphur Proteins and their Significance in the Purification of Extracted Wool Proteins

O'donnel¹,

Thompson²

1962

Aust. Jnl. Of Bio. Sci.

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A study of a low‐sulphur wool keratin derivative in formamide‐water mixtures

DeDeurwaerder

Harrap

1964

Makromol. Chem.

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The properties of the low-sulphur fraction of soluble S-carboxymethyl wool keratin (SCMKA) have been studied in formamide-water mixtures. As the concentration of formamide is increased there is a decrease in both the sedimentation coefficient and the helical content (as estimated from the MOFFITT-YANG parameter b,) until a plateau occurs at about 50 yo (v/v) formamide. These changes are reversible. The sedimentation equilibrium properties of the SCMKA in 60% (v/v) formamide, pH 7, show that on dilution below 0.3% the protein dissociates from particles of molecular weight 70,000 into a minimum of two sub-units. ZUSAMMENFASSUNG: Die Eigenschaften der schwefelarrnen Fraktion von loslichem S-Carboxymethyl-WoUkeratin (SCMKA) wurden in Formamid-Wasser-Mischungen untersucht. Mit zunehmender Formamid-Konzentration nehmen der Sedimentationskoeffizient und der (ans dem MOF-FIT-YANG-Parameter b, geschatzte) Helix-Anteil zu. Bei etwa 50 yo (v/v) Formamid werden die (Xo13en konstant. Die hderungen sind reversibel. I n 60% (v/v) Formamid,pH 7, zeigte der Sedimentationsgleichgewichtsversuch eine Dissoziation des Proteins. Bei einer Verdiinnung unter 0,3 yo spaltet SCMKA vom Molekulargewicht 70 000 in mindestens 2 Untereinheiten a d .

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Studies of an associating protein system: Sub‐unit molecular weight of the low sulphur fraction of soluble wool keratin

DeDeurwaerder

Harrap

1965

Makromol. Chem.

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Solutions of the low-sulphur fraction of soluble S-carboxymethyl wool keratin in 60 yo formamide were previously shown to dissociate on dilution. In order to obtain the molecular weight of the smallest sub-unit present, data are reported using the techniques of osmometry and equilibrium centrifugation a t high speed. Values for Mn and M, a t infinite dilution obtained by both techniques lie in the range 23,000-25,000. The system as a whole probably involves an equilibrium between monomer, dimer, and trimer and the relation of this to the structure of the crystalline part of the wool fibre is discussed. ZUSAMMENFASSUNG:I n einer friiheren Arbeit uber losliches S-Carboxymethyl-Wollkeratin wurde gezeigt, da13 in der Losung der schwefelarmen Fraktion in 60-proz. Formamid bei Verdunnung Dissoziation stattfindet. I n der vorliegenden Arbeit wurden die Molekulargewichte der kleinsten Untereinheit auf osmotischem Wege und aus dem Sedimentationsgleichgewicht bestimmt. Dabei lagen die Werte fiir das Zahlenmittel Mn und das Gewichtsmittel M, bei unendlicher Verdiinnung im Bereich 23 000-25 000. Das geloste System enthat wahrscheinlich ein Gemisch aus Mono-, Di-und Trimeren, die miteinander im Gleichgewicht stehen; dies wurde im Zusammenhang mit der Struktur des kristallinen Teils der Wollfaser untersucht.

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N-Acetyl Groups in Wool and Extracted Wool Proteins

Cited by 24 publications

References 12 publications

Studies on Oxidized Wool VI. Interactions Between High- and Low-'Sulphur Proteins and their Significance in the Purification of Extracted Wool Proteins

Studies on Oxidized Wool VI. Interactions Between High- and Low-'Sulphur Proteins and their Significance in the Purification of Extracted Wool Proteins

A study of a low‐sulphur wool keratin derivative in formamide‐water mixtures

Studies of an associating protein system: Sub‐unit molecular weight of the low sulphur fraction of soluble wool keratin

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