Keratin Hydrolysate Research Articles

Physical and chemical consequences of keratin crosslinking, with application to the determination of crosslink density.

The high levels of covalent disulfide crosslinking in keratins strongly affect (1) structural stability, (2) viscoelasticity, and (3) chemical reactivity. This paper briefly reviews recent work on these subjects, with critical emphasis on methods by which chemical and physical properties can be related to inter-and intra-molecular crosslink density in heterogeneous systems like keratins. Detailed attention is drawn to effects of crosslinking on the hydrolysis of keratin by acids or enzymes. Within the limits of reasonable assumptions, it is possible to account quantitatively for crosslink dependent variations in the hydrolysis rate of different keratins, and also to derive a formula for calculating the absolute intermolecular crosslink density from the amount of keratin dissolved after partial hydrolysis and the number of chain ends appearing in the soluble fraction.

Foaming Property of the Hydrolysis Products of Keratin. I.

The foaming components were fractionated from keratin hydrolysate by membrane ultrafiltration. Molecluar weights, surface tensions, foam heights, and foam stabilities of the above fractions were determined. The molecular weight range of the main foaming components was estimated to be from 1.0×104 to 5.0×103 by means of membrane ultrafiltration. Fractions were subject to gel filtration using TSK-Gel G3000SW and G2000SW in order to check the molecular weight ranges of the membrane ultrafiltrates. The molecular weight of the most abundant component of each fraction was found to correspond well to the molecular weight of the component fractionated by the membrane except those of the molecular weight below 10, 000.

Biological and biochemical studies on a keratinolytic thermo philic actinomycete, isolated from Egyptian soil

A thermophilic actinomycete was isolated from Egyptian soil by an enrichment technique. The organism was identified as a strain of Thermomonospora vulgaris , capable of d gesting native as well as autoclaved keratin (chicken feather). The effect of some factors on the growth of the organism and the percentage of feather hydrolysis was examined. A possible mechanism for keratin hydrolysis was discussed.

Production of pigments similar to those from hair from amino acid and keratin interaction.

SummaryThe soluble pigments produced when fat free nail keratin and tyrosine or tryptophan are boiled together with mineral acids differ from those produced when the keratin or amino acids are treated separately. The reaction involving tryptophan is enhanced by the simultaneous hydrolysis of keratin. Apparently keratin contributes some component (s) to the formation of pigment. The evidence favors the suggestion of Lee and Penrose that the red pigment obtained from human hair by the method of Arnow is not a natural pigment, but one produced from a colorless chromogen during the prolonged acid treatment. The pigment produced by the interaction of keratin and tryptophan in 6 N HO shows an absorption spectrum similar to that of the pigment trichosiderin, but contains no iron. The similarity of the absorption spectra suggests that the organic portion of the natural pigment may be derived in part from tryptophan.

Products of the Hydrolysis of Wool Keratin by Papain

THE study of the action of enzymes on proteins is engaging the attention of a number of workers. The present communication describes the results of an investigation into the products formed when papain acts on wool keratin. This reaction has been described previously1; but little is known about the hydrolysis products.

Observations on the Nutrition of Maggots of Australian Blow-Flies

ABSTRACT Larvae of L. cuprina and Ch. rufifacies are capable of liquefying and digesting protein media without the intervention of bacteria. Both species and L. sericata secrete tryptic and peptic enzymes and at least L. cuprina does so from the moment of hatching. Tryptase is more abundant than pep tase. Predatory activity, though a normal habit of Ch. rufifacies, is not necessary for any of these species and did not occur in the masses of Lucilia larvae used for extraction of the enzymes, although they were kept for periods up to 24 hours without food. Partial development of larvae occurred in sheep dung, faeces-stained wool and in the products of keratin hydrolysis. Complete development took place in wool containing a “gummy crust” of dried exudate and in. some samples of faeces-stained wool. Some of the samples of faeces-stained wool and those containing a “crust” have been demonstrated serologically by Dr I. M. Mackerras to have an increased content of soluble sheep protein as compared with normal wool. A marked increase of soluble protein has been demonstrated in struck wool both chemically and serologically. Moisture, warmth, shelter and aeration are essential physical conditions for larval development. In addition, an alkaline reaction is relatively favourable and an acid reaction relatively unfavourable. There are normally two stages in the development of a primary strike, the first stage being from hatching up to the time the larvae attack the skin, the outer layer or epidermis of which is approximately 36µ thick (Whitnall, 1931). During this stage they must feed, if at all, on materials already present. The second stage is from the commencement of an actual skin lesion up to full development of the maggots. During this stage there is a more or less copious serous exudation, which has been shown to be an adequate food for the full development of the maggots. Faeces-staining, presence of exudate due to a prior lesion, and products of wool hydrolysis have been shown to be adequate to carry the larvae through the first stage. Wool hydrolysis on the living sheep is probably not an important factor, judging by an examination of wool samples, but we have isolated organisms which, when growing on a nutrient medium, are capable of disintegrating wool fibre. The role of bacterial activity in strike is complex and appears to be substantially as follows : (a) to produce substances which attract the flies and stimulate them to oviposit ; (b) to provide food for the initial growth of the maggots, either by rendering assimilable the inert proteins, or by causing a skin reaction with a serous exudation. The immediate work for the future is a more exact determination of: (a) the nature of the food of the larvae in the early stage of growth on the living sheep; (b) the factors which influence its production ; and (c) the mechanism by which the larvae invade the skin.