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- May 20, 2016
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I was doing an MCAT diagnostic test from kaplan. One of the topics was a mutation that caused an enzyme to lose only some of its function but retained most.
I'm confused in general how an enzyme can only lose some part of its function but not all of it. Doesn't losing some function indicate that the active site is somehow defective and this could cause its substrates to be more loosely connected? Does losing "some" function indicate simply a lower activity level?
If the structure of active site is therefore affected then I assumed that the alteration of the primary sequence is the cause and this indicated frameshift...
But kaplan says it's missense b/c an enzyme losing only part of its function indicates some changes to the AA sequence but not all. Frameshift would therefore be too big of a damage for the enzyme even work anymore.
So what is the degree of mutation that would allow an enzyme to retain some function? It stills seems arbitrary to me b/c what if a nonsense mutation stopped the protein at the very end of the sequence but it didn't affect active site? Wouldn't the enzyme still have some function?
I'm confused in general how an enzyme can only lose some part of its function but not all of it. Doesn't losing some function indicate that the active site is somehow defective and this could cause its substrates to be more loosely connected? Does losing "some" function indicate simply a lower activity level?
If the structure of active site is therefore affected then I assumed that the alteration of the primary sequence is the cause and this indicated frameshift...
But kaplan says it's missense b/c an enzyme losing only part of its function indicates some changes to the AA sequence but not all. Frameshift would therefore be too big of a damage for the enzyme even work anymore.
So what is the degree of mutation that would allow an enzyme to retain some function? It stills seems arbitrary to me b/c what if a nonsense mutation stopped the protein at the very end of the sequence but it didn't affect active site? Wouldn't the enzyme still have some function?