40—SELF-CROSS-LINKING IN HEATED KERATIN

Abstract

An account is given of an investigation of the influence of dry heat on wool keratin. It is shown by three different chemical techniques that cross-linking occurs up to a temperature at which the amino-acid decomposition becomes marked. Although Iysinoalanine and lanthionine are shown to be formed, these amino acids do not appear to be major contributors to the cross-linking of the heated protein.

The covalent binding of the ∊-amino group of lysine was determined quantitatively, and, from the results obtained, it is deduced that this group is involved to a large extent in the formation of cross-links.

On the basis of these findings, it is postulated that amide cross-links are formed through the ∊-amino group of lysine by reaction with carboxylic side chains of aspartic or glutamic acids or their amide derivatives.

KEY WORDS (SPECIFIC TERMS):

• SOLUBILITY
• UREA-BISULPHITE SOLUBILITY
• HEAT TREATMENT
• DEGRADATION
• DECOMPOSITION
• SELF-CROSS-LINKING
• FRACTIONATION
• DINITROPHENYLATION
• CHROMATOGRAPHY
• ELECTROPHORESIS
• MERINO WOOL
• KERATIN
• KERATOSE
• KERATEINE
• LYSINE
• LANTHIONINE
• ASPARTIC ACID
• GLUTAMIC ACID
• GLUTAMINE
• ASPARAGINE
• β-AMINOALANINE
• S-CARBOXYMETHYL KERATEINE
• UREA
• SODIUM METABISULPHATE
• POTASSIUM THIOGLYCOLLATE
• PERFORMIC ACID
• AMIDE CROSS-LINKS
• AMINO GROUPS
• DISULPHIDE BONDS

KEY WORDS (BROADER TERMS):

• PHYSICAL-CHEMICAL PROPERTIES
• DEGRADATION PROPERTIES
• CROSS-LINKING
• CHEMICAL ANALYSIS
• WOOL
• PROTEINS
• CROSS-LINKS