Is my answer more correct?

[BlitzSleep]

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In this question it asks what statements are true about prosthetic groups:
I. they are non-protein organic molecules associated with the enzyme
II. they are added to proteins after translation
III. they are needed in order for some enzymes to catalyze reactions

I chose II and III. However, the TPRH workbook says that the answer is I, II, and III. I thought Prosthetic groups can be inorganic molecules (i.e. iron heme group) or am I misunderstanding what a prosthetic group is?

Help please.

 

[docelh]

Prosthetic group is specifically a non-protein molecule. Think about it for a moment. If they were a protein, they would be part of the enzyme or enzyme complex.

 

[Carboxide]

In this question it asks what statements are true about prosthetic groups:
I. they are non-protein organic molecules associated with the enzyme
II. they are added to proteins after translation
III. they are needed in order for some enzymes to catalyze reactions

I chose II and III. However, the TPRH workbook says that the answer is I, II, and III. I thought Prosthetic groups can be inorganic molecules (i.e. iron heme group) or am I misunderstanding what a prosthetic group is?

Help please.

The iron heme INCLUDES an Fe molecule but the actual heme is organic.

http://www.angelo.edu/faculty/kboudrea/molecule_gallery/04_aromatics/heme_01.gif

 

[BlitzSleep]

Prosthetic group is specifically a non-protein molecule. Think about it for a moment. If they were a protein, they would be part of the enzyme or enzyme complex.

I agree, but my argument is that prosthetic groups are also non-protein inorganic molecules.

The iron heme INCLUDES an Fe molecule but the actual heme is organic.

But doesn't the Fe make it inorganic?

 

[docelh]

I agree, but my argument is that prosthetic groups are also non-protein inorganic molecules.

No, that's not correct. It's any non-protein molecule involved in catalysis. Otherwise, it would be protein and part of the enzyme.

 

[BlitzSleep]

No, that's not correct. It's any non-protein molecule involved in catalysis. Otherwise, it would be protein and part of the enzyme.

I apologize if I'm being stubborn, but yes I agree with what you are saying. It is any non-protein molecule.

The statement says organic molecule. With this type of question, everything that is mentioned must be true.

To me, it is saying that only non-protein organic molecules can be prosthetic groups.

When metals are involved, it is inorganic (correct?), for example Iron heme prosthetic group.


Maybe I'm just overanalyzing, but i'm beginning to question the quality of the TPRH workbook (especially since the explaination of Passage 6 #4 talks about NADPH when the problem is about beta oxidation

 

[docelh]

When metals are involved, it is inorganic (correct?), for example Iron heme prosthetic group.

If it's a metal covalently bonded to an organic molecule, the aggregate would be an organic molecule. So heme is an organic molecule, Fe inclusive. Prosthetic group does not rule out non-organic ions or molecules, but most of those tend to be reactants or non-catalytic co-factors.

 

[BlitzSleep]

If it's a metal covalently bonded to an organic molecule, the aggregate would be an organic molecule. So heme is an organic molecule, Fe inclusive. Prosthetic group does not rule out non-organic ions or molecules, but most of those tend to be reactants or non-catalytic co-factors.

Ah alright that makes sense. Thank you docelh & carboxide!