If my protease is in lysosomes and works in the blood to att

If my protease is in lysosomes and works in the blood to attack un-engulfed invaders at which pH would the protein structure remain relatively intact with the hinge closed?

2.3

5

7.2

7.4

9.5

Solution

The correct anser is pH 2.3.

Explanation: The lysosomes represent the site for hydrolyzing enzymes which engulf the foreign material and digest them by hydrolysis. These hydrolytic enzymes can function only at low pH levels or highly acidic conditions. Slightly acidic conditions corresponding to pH of 5 will not help in activation of these enzymes. Importantly, these hydrolyzing enzymes are also found in many of the body secretions such as mucus and tears. Together, they represent the second life of body defence and immunity by physico-chemically destructing the invading pathogen/invader molecules. At this relatively low pH of 2.3, the protein structure of these proteases remains conserved, does not deteriorate and functional as well.