Pepsin prac and changing pH

and any other non-chem subjects.
Post Reply
User avatar
rae
Posts: 1045
Joined: 31 May 2006, 10:00
School: Oxley College
Suburb: Burradoo
State/Location: NSW

Pepsin prac and changing pH

Post by rae »

Please Help!!

We are about to do the enzyme prac with pepsin and egg whiteand changing the pH.
Can any one suggest easy solution to use to achieve pH 2, pH6/7 and pH9? What molarities??

I was thinking acetic acid and sodium bicarb am I on the right track?

Lorrae
User avatar
Whspa
Posts: 345
Joined: 01 Jun 2006, 10:00
State/Location: NSW

Re: Rennin prac and changing pH

Post by Whspa »

I've had success with this:

pH2 0.01M hydrochloric acid
pH3 80mL 0.1M citric acid plus 20mL 0.2M disodium hydrogen phosphate
pH4 62mL 0.1M citric acid plus 38mL 0.2M disodium hydrogen phosphate
pH5 48mL 0.1M citric acid plus 52mL 0.2M disodium hydrogen phosphate
pH6 37mL 0.1M citric acid plus 63mL 0.2M disodium hydrogen phosphate pH7 18mL 0.1M citric acid plus 82mL 0.2M disodium hydrogen phosphate
pH8 3mL 0.1M citric acid plus 97mL 0.2M disodium hydrogen phosphate
pH10 0.1M sodium hydroxide

These solutions are sufficiently accurate for use in the cell membrane activity in Biology and also for general pH testing
Carol
User avatar
rae
Posts: 1045
Joined: 31 May 2006, 10:00
School: Oxley College
Suburb: Burradoo
State/Location: NSW

Re: Pepsin prac and changing pH

Post by rae »

Does this mean, if I add these buffers to a pepsin solution they will end up being the pH of the buffer??
User avatar
Whspa
Posts: 345
Joined: 01 Jun 2006, 10:00
State/Location: NSW

Re: Pepsin prac and changing pH

Post by Whspa »

I add the pepsin directly to the buffers.
Carol
User avatar
Mother
Posts: 275
Joined: 17 May 2006, 10:00
Job Title: Science lab. technician
School: Dubbo College/Senior Campus
Suburb: Dubbo
State/Location: NSW

Re: Pepsin prac and changing pH

Post by Mother »

I'll come in on this one Carol.

Pepsin powder or a pepsin solution?
User avatar
Whspa
Posts: 345
Joined: 01 Jun 2006, 10:00
State/Location: NSW

Re: Pepsin prac and changing pH

Post by Whspa »

Pepsin powder
Post Reply