Notable enzymes/systems that use prothetic groups

[RH8448]

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I was surprised to see on the practice exam the question about cytochrome c and how many electrons it carries. Naturally, because all of the other molecules carry two electrons at a time I said two. Cytochrome carries one apparently because it has a heme group. What other notable molecules work like this? Molecules that use either heme or another metal that is worth knowing? I know the heme groups in blood of course. Also, to go in slightly another direction, how exactly does heme bind oxygen because oxygen is neutral?

 

[chemist16]

I'm not sure about your other questions but the iron center binds the oxygen. Rather, in organometallic terms, it coordinates the oxygen as a ligand. You don't need polarization of charges for a metal to coordinate a ligand - just like how a metal can coordinate an olefin. Basically the axial sites of the iron center are open and the dz^2 orbital can be used to form an MO with the pi bonding orbital of the oxygen.

 

[basophilic]

I was surprised to see on the practice exam the question about cytochrome c and how many electrons it carries. Naturally, because all of the other molecules carry two electrons at a time I said two. Cytochrome carries one apparently because it has a heme group. What other notable molecules work like this? Molecules that use either heme or another metal that is worth knowing? I know the heme groups in blood of course. Also, to go in slightly another direction, how exactly does heme bind oxygen because oxygen is neutral?

one-electron reductions in ETC proteins as opposed to 2-electron reductions/oxidations like in NADH is an important concept that you should be aware of - it's the reason why you need flavin electron carriers, which can undergo 1 OR 2 electron oxidations/reductions
other heme-using proteins: cytochrome oxidase has 2 (Fe/Cu based), cytochrome p450 (which has role in apoptosis and cancer), catalase, and many more; vitamin B12 uses Co-heme organometallic catalyst
As far as cofactors/prosthetic groups go, you might be better off understanding how the individual cofactors/prosthetic (i.e. TPP, PLP, biotin, metal ions, etc.) work; like if you know biotin's general role is to carboxylate then it's used by various carboxylases like pyruvate carboxylase; TPP works to decarboxylate, etc.
for heme-O2 binding, see above explanation