[scientizscht (OP)]

Hello!

For reactions that occur inside water solutions and have oxygen as one of the substrates, how much does oxygen limit these reactions?

Oxygen inside water is normally very low and also the oxygen from the atmosphere does not easily diffuse inside the water to replenish any consumed oxygen.

Can you help me please estimate what is the bottleneck that oxygen poses for oxygen consuming reactions inside water solutions?

Thanks!

[evan_au]

Life is one of those "reactions" that occurs in water.

Cold water can hold more oxygen than warm water, so as the oceans warm due to human activities, the amount of life the oceans can sustain will drop. (...not helped by overfishing!)

See: https://en.wikipedia.org/wiki/Oxygen#Physical_properties

[scientizscht (OP)]

Life is one of those "reactions" that occurs in water.

Cold water can hold more oxygen than warm water, so as the oceans warm due to human activities, the amount of life the oceans can sustain will drop. (...not helped by overfishing!)

See: https://en.wikipedia.org/wiki/Oxygen#Physical_properties

Thanks for the information but not really helpful.
I need to know whether oxygen is the limiting factor in oxygen reduction for oxygen-using oxidising enzymes in water solutions.

[Bored chemist]

I need to know whether oxygen is the limiting factor in oxygen reduction for oxygen-using oxidising enzymes in water solutions.

It depends.

[scientizscht (OP)]

I need to know whether oxygen is the limiting factor in oxygen reduction for oxygen-using oxidising enzymes in water solutions.

It depends.

Everything depends. Any indications?

[Bored chemist]

Any indications?

No, you have not provided any indications.
Would you like to, or is this another of your posts where you ask a stupidly open question then get upset when it's impossible for anyone to answer.

[scientizscht (OP)]

Any indications?

No, you have not provided any indications.
Would you like to, or is this another of your posts where you ask a stupidly open question then get upset when it's impossible for anyone to answer.

You equally do not indicate what more information you need.

There are tons of such enzymes and reactions, I do not have a specific in mind.

One example would be glucose oxidase. In a glucose solution of 100mM, the oxygen dissolved would be 0.22mM. The question is simple: will oxygen impede the glucose oxidation as it is three magnitudes smaller?

[Bored chemist]

The question is simple: will oxygen impede the glucose oxidation as it is three magnitudes smaller?

And the answer is also simple.

It depends.

[scientizscht (OP)]

The question is simple: will oxygen impede the glucose oxidation as it is three magnitudes smaller?

And the answer is also simple.

It depends.

On what and how?

[Bored chemist]

On what and how?

Guess.

[charles1948]

In refusing to give a straight answer to the OP's question, posters are merely displaying proper scientific caution.

Which is admirable, though not very helpful perhaps

[Bored chemist]

In refusing to give a straight answer to the OP's question, posters are merely displaying proper scientific caution.

Which is admirable, though not very helpful perhaps

Actually I'm trying to teach the OP to ask better questions.
He has a tendency to ask things which, to answer fully,  would need a book or two.
For example, a full reply to this thread would need a good understanding of enzyme kinetics and of diffusion.
It's unrealistic to imagine that someone is going to provide that here.

The OP would do much better by learning science from the Khan Academy or some such.

This has been pointed out before, but he persists in asking  absurd questions.


You could help me by letting me know if this explanation made sense to you.
It could be that I'm not making myself clear to the OP.

[scientizscht (OP)]

My question has several assumptions which are easy to assume.

E.g. we have glucose oxidase in a still solution with glucose. Let's say we have 10,000 units and the concentration of glucose is 10mM. The question is, will oxygen diffuse from air into the water and react with the enzyme or this will not be enough and the enzyme will be restricted?

I am assuming room temperature, normal atmosphere, etc etc. I am not referring to extreme situations where we have 5kg of enzyme per litre or superheated water etc.

If the answer depends, I am asking what conditions would oxygen start limiting the reaction.

I do not understand what you find unanswerable in my question.

Of course, it will need to read 2 books to answer this but I don't want the answer to be two books, I want the conclusion from people who have relevant knowledge and experience or can provide estimates.

[Bored chemist]

I want the conclusion from people who have relevant knowledge and experience or can provide estimates.

That is clearly not true.
Because you have been given that answer twice,.
Here it is for the third time

Quote from: Bored chemist on 26/12/2020 14:56:09
It depends.

[Bored chemist]

The question is, will oxygen diffuse from air into the water

Obviously, yes

Life is one of those "reactions" that occurs in water.

A lot of "life" involves the enzymatic oxidation of glucose.
But you didn't want that answer either.

[scientizscht (OP)]

The question is, will oxygen diffuse from air into the water

Obviously, yes

Life is one of those "reactions" that occurs in water.

A lot of "life" involves the enzymatic oxidation of glucose.
But you didn't want that answer either.

I obviously know that but I am not sure if it is representative of regular lab conditions, i.e. considerable glucose concentration and considerable enzyme concentration. Also, oxygen is heavily facilitated and transported and stored in cells so I do not think that a living organism oxidising glucose is representative of a 50mM glucose solution with 10,000 units of enzyme under ambient air and no stirring.

[Bored chemist]

Obviously, with no stirring, the reaction is going to be much slower further from the surface.
So the "rate of reaction" isn't going to be well defined, is it?

What are you actually trying to find out?

[charles1948]

Obviously, with no stirring, the reaction is going to be much slower further from the surface.
So the "rate of reaction" isn't going to be well defined, is it?

What are you actually trying to find out?

Never come the raw prawn with Bored.  He knows all the lurks.

[scientizscht (OP)]

Obviously, with no stirring, the reaction is going to be much slower further from the surface.
So the "rate of reaction" isn't going to be well defined, is it?

What are you actually trying to find out?

I put glucose oxidase in an unstirred glucose solution under ambient conditions and no glucose reacted. I want to know if oxygen is responsible for that.

[Bored chemist]

no glucose reacted

How do you know?

But, the most likely answer is that diffusion from the air into your reaction vessel was too slow.
Did you put the solution in a shallow flat tray, a beaker or a conical flask?