Question

In the following flowchart about protein digestion, P, Q, R and S are enzymes.
Proteins $\stackrel{P}{\to }$ Proteoses and Peptones $\stackrel{Q}{\to }$
Polypeptides $\stackrel{R}{\to }$ Dipeptides $\stackrel{S}{\to }$ Amino acids
The correct information of enzymes P, Q, R and S is

• A. P: Produced by intestine as a proenzyme stage and is activated at alkaline pH
  
  Q: Produced by pancreas as acts a proenzyme and is activated by an intestinal enzyme
  
  R: Produced by stomach as a proenzyme stage and is activated at acidic pH
  
  S: Produced by pancreas in an active state
• B. P: Produced by stomach as a proenzyme stage and is activated at acidic pH
  
  Q: Produced by pancreas as acts a proenzyme and is activated by an intestinal enzyme
  
  R: Produced by pancreas in an active state
  
  S: Produced by intestine in an active state
• C. P: Produced by stomach as a proenzyme and is activated at acidic pH
  
  Q: Produced by pancreas as a proenzyme and is activated by an intestinal enzyme
  
  R: Produced by intestine in an active state
  
  S: Produced by intestine in an active state
• D. P: Produced by stomach as a proenzyme stage and is activated at acidic pH
  
  Q: Produced by pancreas as a proenzyme and is activated by an intestinal enzyme
  
  R: Produced by intestine as a proenzyme and is activated by Q
  
  S: Produced by intestine in an active state

Answer 1

Answer: (C)

P- pepsin produced by stomach as pepsinogen. It is activated at acidic pH. It converts proteins into proteoses and peptones. Q- Trypsin or chymotrypsin produced by pancreas as trypsinogen or chymotrypsinogen. Trypsin is activated by enterokinase from the intestine. It can convert peptones and proteoses to polypetides. R- Aminopeptidase produced intestine in an active form. R could also be carboxypeptidase produced by pancreas as procarboxypeptidase. Both of them can convert polypetides to dipeptides. In this contect it is aminopeptidase. S is dipeptidase produced by intestine in an active form. It converts dipeptides to amino acids