The Lock and Key Hypothesis.
The LOCK and KEY Hypothesis was proposed by a scientist, Emil Fischer.
According to Emil Fischer, "The lock is the equivalent to that of an enzyme while the key is portrayed as the substrate."
To further support his statement, he gave the following idea:
"Like an enzyme, the lock can be reused many times as it remains chemically unchanged at the end of the reaction. Also, the fact that reactions occur only at the active site, or binding site, is showed as the key only being able to open the lock only at the keyhole, not anywhere else."
Now this is where you have to THINK and question the statement.
Why ?
Well, now look; everyone knows that it is the lock that opens and changes its basic structure after the key has been inserted in to it.
Now considering the enzyme, it is not altered and does not change it's shape or structure after the reaction.
The substrate on the other hand loses its primary structure, and is either broken down or converted into any new form.
ALERT !! THEORY CONFLICT !!!
Now, if we refer to the Enzyme as the Lock, well then according to the above explanation, the theory is completely void. Because, a Lock changes shape every time we insert a key into it ! While on the other hand, they Key remains unchanged !
Its not like we have to purchase a key every now and then from the hardware store to open the same old lock !
By looking at the following diagram, you will see that it is the SUBSTRATE that loses its original form and not the ENZYME ! So, logically, you cannot refer to the Enzyme as the lock because as we can see, the Enzyme's structure remains the same throughout the reaction.
Illustrated diagram of the Lock AND KEY HYPOTHESIS.
END OF DISCUSSION.
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Thankyou for your time !
