bromochloroacetic-acid and 2-mercaptoacetate

Keratin has been attracting interest due to its stability against enzymatic degradation thereby allowing more predictable degradation profile for tissue regeneration applications. While the efficacy of keratin has been demonstrated in different tissue models, there has been no systematic study to investigate and compare the different routes of keratin extraction from human hair. Here, we compared the four commonly used extraction methods and highlighted both physical and chemical differences in the extracted keratin. Keratin was extracted from human hair using one of four common agents, namely, sodium sulfide, peracetic acid, urea and thioglycolic acid. Whereas no specific trend was observed, the keratin extracted through peracetic acid method had significantly different properties. It resulted in lowest yield of 52 μg/mL and low crystallinity but the protein formed aggregates with highest hydrodynamic average size of around 283 nm compared to the other three methods. However, despite greater aggregation, keratin extracted from peracetic acid method exhibited secondary structural conformation similar to thioglycolic acid method. All the four extracted keratin promoted cellular proliferation of osteoblasts compared to the uncoated surface. These results provide new insight into the extraction of keratin from human hair with implications for its use as a biomaterial.

Topics: Chemical Fractionation; Hair; Humans; Keratins; Particle Size; Peracetic Acid; Protein Structure, Secondary; Thioglycolates

It has been established after conducting an X-ray diffraction study of the structure of hair treated with the thioglycolic acid solution that the preferable location of thioglycolic acid molecules should be the intrafibrillar unordered areas. Based on this fact it has been concluded that the redistribution of disulphide bonds of hair occurs mainly in the mentioned above areas when treated with thioglycolic acid solution.

Topics: Hair; Humans; Keratins; Protein Conformation; Thioglycolates; X-Ray Diffraction

This study was developed to purify and to characterize a keratinolytic protease from the bacterium Microbacterium sp. strain kr10.. Enzyme purification was carried out by sequential liquid chromatography on Sephadex G-100 and Q-Sepharose columns. The purification was about 255-fold, with a yield of 34%, as determined with azocasein as substrate. The molecular weight of the enzyme was estimated as 42,000 Da by SDS-PAGE. The enzyme had pH and temperature optima of 7.5 and 50 degrees C respectively. This keratinase was inhibited by EDTA and 1,10-phenanthroline, and analysis of metal content indicates that Zn(2+) and Mg(2+) are present. A 2(2) factorial design was developed to investigate the effect of keratinase and mercaptoacetate concentration on feather keratinolysis. Statistical analysis showed that both variables have a significant effect on hydrolysis of keratin.. A new keratinase produced by Microbacterium sp. was purified and characterized.. This keratinolytic enzyme offers an interesting potential for the hydrolysis of keratin wastes to be used as feed supplement or bioconversion to added-value products.

Topics: Animals; Chromatography, Liquid; Edetic Acid; Electrophoresis, Polyacrylamide Gel; Enzyme Inhibitors; Feathers; Hydrogen-Ion Concentration; Industrial Microbiology; Keratins; Magnesium; Molecular Weight; Mycobacterium; Peptide Hydrolases; Phenanthrolines; Temperature; Thioglycolates; Zinc

In order to investigate the reduction mechanism of L-cysteine (Cys) on keratin fibers, cross-sectional samples of virgin white human hair treated with Cys were prepared. The heterogeneous reaction between Cys and keratin fibers involving the diffusion of Cys into human hair was analyzed at the molecular level using microspectrophotometry and Raman spectroscopy. The diffusion pattern of Cys into human hair showed non-Fickian type characteristics, thus indicating the free amino groups of electrostatically interacted with the anionic ions of the fiber surface. The disconnected relative concentration of -SS- groups at various depths of the hair samples with pH 9.0 was less than the Cys relative concentration, indicating that the reaction rate (the disconnection of -SS- groups) was slower than the diffusion rate of Cys into human hair. From these experiments, we concluded that the free amino groups of Cys electrostatically interacted with the anionic ions of the fiber surface, thereby decreasing the reaction rate (the disconnection of -SS- groups) of Cys at pH 9.0.

Topics: China; Cysteine; Diffusion; Disulfides; Hair; Hair Color; Humans; Hydrogen-Ion Concentration; Keratins; Kinetics; Microspectrophotometry; Oxidation-Reduction; Spectrum Analysis, Raman; Static Electricity; Temperature; Thioglycolates

Topics: Antigens; Glycols; Hair; Keratins; Thioglycolates