All the organophosphate compounds listed in able undergo hydrolysis reactions in the same way as ATP. The following equation illustrates the situation for glucose-1-phosphate?

Glucose-1-phosphate + H2O → Glucose + Pi

∆G°'= -20.9 kJ/mol

Using the free energy values in table 15.1, predict whether the following reactions will proceed in the direction written, and calculate the ∆G°' for the reaction, assuming that the reactants are initially present in a 1:1 molar ratio

ATP + creatine → Creatine phosphate + ADP
answer: Will not proceed as written ∆G°' = +12.6 kJ

ATP + glycerol → glycerol-3-phosphate + ADP
answer: Will proceed as written ∆G°^' = -20.8 kJ

ATP + pyruvate → phosphoenolpyruvate + ADP
answer: Will not proceed as written ∆G°' = +31.4 kJ

ATP + Glucose → glucose-6-phosphate + ADP
answer: Will proceed as written ∆G°' = -18.0 kJ

I am unsure how this works.

@frostbite

Question

All the organophosphate compounds listed in able  undergo hydrolysis reactions in the same way as ATP. The following equation illustrates the situation for glucose-1-phosphate?

Glucose-1-phosphate + H2O → Glucose + Pi

∆G°'= -20.9 kJ/mol

Using the free energy values in table 15.1, predict whether the following reactions will proceed in the direction written, and calculate the ∆G°' for the reaction, assuming that the reactants are initially present in a 1:1 molar ratio
 
	ATP + creatine → Creatine phosphate + ADP
	answer: Will not proceed as written ∆G°' = +12.6 kJ

ATP + glycerol → glycerol-3-phosphate + ADP
	answer: Will proceed as written ∆G°^' = -20.8 kJ

ATP + pyruvate → phosphoenolpyruvate + ADP 
	answer: Will not proceed as written ∆G°' = +31.4 kJ

ATP + Glucose → glucose-6-phosphate + ADP 
	answer: Will proceed as written ∆G°' = -18.0 kJ

I am unsure how this works.

@frostbite

summersnow8 · Answer

attachment

frostbite · Answer

What is it exactly you are unsure about? The answers are they not yours?

frostbite · Answer

Sorry it toke me so long to get here. I had to get something to eat, but now you have my full attention!

summersnow8 · Answer

Those are the correct answers, but I am not sure how to get them. i know you are suppose to use the table, but when I try and set it up, I don't get the right answer

frostbite · Answer

Alright. Let me fast try see if I can get the first one correct. Then I can try explain it to you! :)

summersnow8 · Answer

okay, thanks

frostbite · Answer

No problem. I feel I kinda owe it to you when I had to let you down on the huge document you sent.

summersnow8 · Answer

nah, it's okay

frostbite · Answer

Alright. Lets go:

Remember Hess law?

summersnow8 · Answer

I believe so

frostbite · Answer

Alright. So when you worked with Hess's law in some chemistry class you were tolded it work for enthalpy (H), but now you have to take my word for it also works for the gibbs free energy as they are both state functions (and I love to prove this to you later some day):

We are given the reactions for the hydrolysis of the phosphate groups of different organophosphate compounds. For the first reaction we got:
ATP + creatine → Creatine phosphate + ADP

Using Hess's law we can spit up the reaction in two reactions:
1) the hydrolysis of ATP: ATP + H2O -> ADP + Pi
2) The hydrolysis of phosphocreatine: Creatine phosphate + H2O -> Creatine + Pi.

Notate that if we want the reaction in the question we need to flip reaction 2 and use the relation:$$\Large \Delta G^\circ (A \rightarrow B)=-\Delta G(B \rightarrow A)$$

Hess law then state we need to sum all the reactions we need to obtained the wished reaction:
$$\Large  \Delta G^\circ _{reaction}=\Delta^\circ G(1)+(-\Delta G^\circ(2))$$

frostbite · Answer

In other words for question one:
$$\Large \Delta G^\circ=-30.5 + 43.1 =12.6~ kJ/mol$$

summersnow8 · Answer

I was wondering what this had to do with it: 

Glucose-1-phosphate + H2O → Glucose + Pi

∆G°'= -20.9 kJ/mol

summersnow8 · Answer

That makes sense to me, do I use the hydrolysis of ATP for the rest of the problems?

frostbite · Answer

Looks like it yes :)

summersnow8 · Answer

I guess I am confused on how it choose the compounds?

summersnow8 · Answer

to*

frostbite · Answer

Shall I make a more complete example of the first one to show all my thoughts and calculations?

summersnow8 · Answer

we did a few examples in class. I just want to make sure I understand it.

frostbite · Answer

Ah. If you want you can do the rest and I check. But it is as simple as choosing the correct reactions from the table, and then setup the reactions correct so it all cancel to give the wished reaction.

summersnow8 · Answer

okay. I'll set some up and have you look at them

frostbite · Answer

Sounds good. Then I will make a cup of tea in the mean while.

summersnow8 · Answer

ATP + H2O → ADP + Pi 				                     -30.5 kJ/mol
Glycerol-3-phosphate + ADP → ATP  glycerol                +9.7 kJ/mol
                                                                                       -20.8 kJ 

ATP + H2O → ADP + Pi 				                     -30.5 kJ/mol
PEP + ADP → ATP + pyruvate				               61.9 kJ/mol
                                                                                     +31.4 kJ

ATP + H2O → ADP + Pi 				                     -30.5 kJ/mol
G6P + ADP → ATP + Glucose				              12.5 kJ/mol
                                                                                     -18.0 kJ

frostbite · Answer

A little unsure about the notation but it looks good and correct.

summersnow8 · Answer

about what notation?

frostbite · Answer

ATP + H2O  ADP + Pi 				                     -30.5 kJ/mol
glycerol + Pi → Glycerol-3-phosphate + H2O               +9.7 kJ/mol
ATP + glycerol → glycerol-3-phosphate + ADP             -20.8 kJ/mol

Is this what you meant?

summersnow8 · Answer

yeah, so things cancel out

frostbite · Answer

In that case 100% correct.