Extraction and characterization of keratin from bovine hoof: A potential material for biomedical applications.

Prachi Kakkar,Ganesh Shanmugam,Balaraman Madhan

doi:10.1186/2193-1801-3-596

Prachi Kakkar, Ganesh Shanmugam + Show 1 more

Open Access

https://doi.org/10.1186/2193-1801-3-596

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Abstract

Keratin from the hoof is a less explored source for making valuable products. In this paper we present the extraction of pure keratin from bovine hooves and characterized them to better address the possible exploitation of this bio-resource as an alternative material for tissue engineering applications. The keratin protein from the pulverized hooves was extracted by reduction, which was observed to be pure, and two polypeptide chains of molecular weight in the range of 45–50 and 55–60 KDa were determined using SDS-PAGE assay. FTIR analysis complementing circular dichroism (CD) data, established that hoof keratin predominantly adopted α-helical conformation with admixture of β-sheet. The keratin was shown to have appreciably high denaturation temperature (215°C) as indicated by differential scanning calorimetric (DSC) analysis. Thermogravimetric analysis (TGA) also showed the retention of 50% of the original weight of the sample even at a temperature of 346°C. The keratin from the hoof had been observed to be biocompatible when analyzed with MTT assay using fibroblast cells, showing more than 90% cell viability. Hence, hoof keratin would be useful for high value biomedical applications.

Highlights

A broad category of insoluble proteins that associate as intermediate filaments (IFs), a cytoskeletal element with 8–10 nm diameter, were being referred to the term “keratin”
The optimum pH range adopted for extraction was 6–8, as keratin could not be extracted at acidic pH and is likely to undergo decomposition at alkaline pH
Band and the appearance of weak amide II bands at 1516 cm−1 (Figure 4D) suggest that keratin adopts admixture of β-sheet conformation in the solid state. These results reveal that the secondary structure of keratin in the film and solid states are similar

Summary

Introduction

A broad category of insoluble proteins that associate as intermediate filaments (IFs), a cytoskeletal element with 8–10 nm diameter, were being referred to the term “keratin”. Apart from being the principal constituent of the stratum corneum of human and animal skin, keratins are found in exoskeletal materials such as horns, hooves, hair, feathers, wool and nails (Aluigi et al 2007; Gupta and Nayak 2014). Keratins (mammalian) were categorized into two distinct groups namely hard and soft, based on their structure, function and regulation. Hard keratins form ordered arrays of IFs embedded in a matrix of cystine rich proteins and contribute to the tough structure of epidermal appendages, whereas soft keratins preferentially form loosely-packed bundles of cytoplasmic IFs (Coulombe et al 2000; Fraser et al 1986; Moll et al 1982) and typically contain less sulphur (Zoccola et al 2009).

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