The key difference between alpha keratin and beta keratin is that the alpha keratin occurs in mammals whereas the beta keratin occurs in the epidermis of reptiles.
Keratin is a broad group of protein, and we can define it as a fibrous protein that forms the main structural constituents of hair, feathers, claws, horns, etc. The alpha keratin and beta keratin are two forms of keratin, which occurs in animals. The difference between alpha keratin and beta keratin lies upon the type of animal that we can find each keratin.
CONTENTS
1. Overview and Key Difference
2. What is Alpha Keratin
3. What is Beta Keratin
4. Side by Side Comparison – Alpha Keratin vs Beta Keratin in Tabular Form
5. Summary
What is Alpha Keratin?
Alpha keratin is a type of protein that we can find in mammals. This protein occurs in hair, horns, nails and the epidermal layer of skin. We can categorize it as a fibrous, structural protein. This means alpha keratin contains amino acids that form a repeating secondary structure. This structure resembles the traditional alpha helix structure of a protein. Moreover, it forms a coiled coil. Due to this structure, it acts as a strong biological material for various uses in mammals.
In our body, this protein synthesizes from protein biosynthesis. The process utilizes the transcription and translation as well. However, when the cells mature, and there is more than enough alpha keratin in the cell, it dies. This creates a strong, non-vascular crust of keratinized tissues.
Figure 01: Structure of Alpha Keratin
Typically, alpha keratin is high with alanine, leucine, arginine and cysteine. These amino acids contribute to form a right-handed helix structure and a left-handed helical structure. We call it, “coiled coil”. When considering the properties of this protein, it has high structural stability. When it exposes to mechanical stress, this protein can retain its structure and shape, protecting what it surrounds. Under high tension, it can convert into beta keratin as well.
What is Beta Keratin?
Beta keratin is a structural protein that occurs mainly in the epidermis of reptiles. The name of this protein has given to it because of its occurrence; it occurs as components in epidermal stratum corneum that is rich in stacked beta pleated sheets. This has led to name it as “corneous beta-proteins” or “keratin associated beta proteins” instead of beta keratin because the term keratin originally refers to alpha keratin.
This protein can add much more rigidity to the skin of the reptiles. Moreover, it provides them with waterproofing and prevention of desiccation. Apart from that, the avian family also may contain this protein. For example, in birds, scales, beaks, claws and feathers may contain beta keratin.
What is the Difference Between Alpha Keratin and Beta Keratin?
Alpha keratin is a type of protein that we can find in mammals whereas beta keratin is a structural protein which occurs mainly in the epidermis of reptiles. This is the key difference between alpha and beta keratins. When considering their occurrence, alpha keratin occurs in hair, horns, nails and the epidermal layer of skin while beta keratin occurs in reptile skin; in epidermal stratum corneum in their skin that is rich in stacked beta pleated sheets. In addition to that, another difference between alpha and beta keratin is that the alpha keratin provides the mammals with structural stability whereas the beta keratin provides rigidity to the skin, waterproofing, and prevention of desiccation for the reptiles.
Summary – Alpha Keratin vs Beta Keratin
Alpha and beta keratin are two forms of structural proteins. Therefore, there are few differences between them. The occurrence of these proteins is the key difference between alpha keratin and beta keratin. That is, the alpha keratin occurs in mammals whereas the beta keratin occurs in the epidermis of reptiles.
Reference:
1. “Alpha-Keratin.” Wikipedia, Wikimedia Foundation, 25 July 2018. Available here
2. “Beta-Keratin.” Wikipedia, Wikimedia Foundation, 17 Aug. 2018. Available here
Image Courtesy:
1.”Keratin creation red”By Mlpatton – Own work, (CC BY-SA 4.0) via Commons Wikimedia
This was a really helpful article, so thank you for writing! I’m curious about one part- you said that alpha keratin can convert to beta keratin under high tension. How does that work? What situations could cause high enough tension on an alpha keratin coil to convert it to beta keratin?