In which scleroprotien?

Scleroproteins are a category of fibrous structural proteins, with keratin being one of the most well-known examples. Keratin is found in hair, nails, and the outer layer of skin, providing strength and protection. Other examples of scleroproteins include collagen, which is essential for the structural integrity of connective tissues, and elastin, which allows tissues to resume their shape after stretching. These proteins are typically insoluble and play critical roles in the structural framework of various biological systems.