203k views
5 votes
Which of the following is most likely incorrect?

a) A comparison of the X-ray structures of chymotrypsin and chymotrypsinogen reveals that the conformations of their active site Asp, His, and Ser residues are virtually identical
b) Zymogen can catalyze hydrolysis extremely slowly
c) The substrate specificity pocket in chymotrypsinogen is incompletely formed
d) The oxyanion hole in chymotrypsinogen is incompletely formed
e) Activation of chymotrypsinogen by trypsinogen is an example of autoactivation

1 Answer

1 vote

Final answer:

The statement 'Activation of chymotrypsinogen by trypsinogen is an example of autoactivation' is most likely incorrect because trypsinogen is the inactive form of trypsin, and the activation of chymotrypsinogen involves the action of trypsin, not an autoactivation process.

Step-by-step explanation:

Among the options given, the most likely incorrect statement is e) Activation of chymotrypsinogen by trypsinogen is an example of autoactivation. Trypsinogen is the inactive zymogen form of trypsin, not chymotrypsin. Chymotrypsinogen is converted to its active form, chymotrypsin, by the action of the enzyme trypsin, not trypsinogen. This process is not considered autoactivation as it involves a different enzyme (trypsin) to activate chymotrypsinogen, not the activation of a zymogen by itself.

A zymogen such as chymotrypsinogen generally does not have its active catalytic sites fully formed, as seen in options c) The substrate specificity pocket in chymotrypsinogen is incompletely formed and d) The oxyanion hole in chymotrypsinogen is incompletely formed. Additionally, statement b) Zymogen can catalyze hydrolysis extremely slowly could theoretically be correct in that a zymogen might have some very low level of catalytic activity prior to activation, though typically not enough to be functionally relevant.

User Bukzor
by
8.3k points