Which statement about keratinase in dermatophyte infections is most accurate?

• A. Keratinase is a viral protease required for assembly of dermatophyte virions in infected tissue.
• B. Keratinase is a bacterial toxin that inhibits keratin synthesis by blocking ribosomal translation.
• C. Keratinase is an enzyme produced by dermatophytes that helps them degrade keratin in skin, hair, and nails.
• D. Keratinase is an enzyme produced by human keratinocytes to cross-link keratin during cornification.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the biological context of keratinase. Keratinase is an enzyme associated with dermatophytes, which are fungi that infect keratinized tissues such as skin, hair, and nails.
2. Step 2: Recognize that keratinase functions by breaking down keratin, a tough, fibrous protein that forms the structural component of these tissues. This degradation allows dermatophytes to invade and colonize the host tissue.
3. Step 3: Evaluate the incorrect options: keratinase is not a viral protease, so it is not involved in viral assembly; it is not a bacterial toxin, so it does not inhibit keratin synthesis by blocking ribosomal translation; and it is not produced by human keratinocytes for cross-linking keratin during cornification.
4. Step 4: Conclude that the most accurate statement is that keratinase is an enzyme produced by dermatophytes to degrade keratin in skin, hair, and nails, facilitating infection.
5. Step 5: Summarize that keratinase's role is enzymatic degradation of keratin, which is essential for dermatophyte pathogenicity in keratinized tissues.