Proteins in Silk
Silk is made up of two main proteins, fibroin and sericin (Lancashire, 2011). Figure 1 illustrates the two main components of silk.
Fibroin
|
Sericin
|
Because silk is composed of fibroin and sericin which are proteins, it is a polypeptide. This means it is a long chain of proteins strung together to make one large substance. Each protein contains a smaller sequence of amino acids. These amino acids are known as the building blocks of all proteins.
Together, silk is made up of 16-18 base amino acids as well as hundreds of smaller acids which are not significant because of their similarity (Karmakar, 1999). The amino acids that are present in silk depend on two main factors; the species of the silkworm and the silkworm's diet (Pierson, 1999). Very similar to human's DNA, both proteins contain their own sequence of amino acids (Lancashire, 2011). Sericin does not have it's own distinguishable DNA sequence because of its small size (Karmakar, 1999). Fibroin is large enough to have its own amino acid sequence, which is displayed in Figure 2 (Lancashire, 2011).
Together, silk is made up of 16-18 base amino acids as well as hundreds of smaller acids which are not significant because of their similarity (Karmakar, 1999). The amino acids that are present in silk depend on two main factors; the species of the silkworm and the silkworm's diet (Pierson, 1999). Very similar to human's DNA, both proteins contain their own sequence of amino acids (Lancashire, 2011). Sericin does not have it's own distinguishable DNA sequence because of its small size (Karmakar, 1999). Fibroin is large enough to have its own amino acid sequence, which is displayed in Figure 2 (Lancashire, 2011).
Fun Fact!
The main protein in silk, glycine, is also a main component in the DNA of human!