Keratin may be grouped as $\alpha$-keratin or $\beta$-keratin after examining protein structure. Suggest the level of protein structure used to classify a protein as $\alpha$-keratin or $\beta$-keratin.
Protease enzymes hydrolyse proteins. A number of proteases can hydrolyse more than one kind of protein. Suggest why a protease may be able to act on different types of protein.
Keratinases are proteases that differ in how much keratin they can hydrolyse. Feathers are not easily broken down because keratin is a very stable protein. Suggest features of keratin structure that help to make it stable.
To break down industrial feather waste, it is beneficial to use keratinases that maintain at least $60\%$ relative activity across a wide range of temperature and pH. Table 2.1 gives, for each keratinase, the temperature and pH working ranges in which at least $60\%$ relative activity is achieved. Use Fig. 2.1 and Fig. 2.2 to complete Table 2.1 and then use the finished table to: • name the keratinase with the broadest temperature working range • name the keratinase with the broadest pH working range.
Some detergents include proteases to remove stains from clothes. These enzymes show high relative activity under alkaline conditions. The scientists stated that K12 and A22 could be appropriate for use in the detergent industry. Using Fig. 2.1 and Fig. 2.2, discuss the advantages and disadvantages of using K12 and A22 in the detergent industry.