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Topic: properties of an engineered protein  (Read 4237 times)

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Offline yolop

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properties of an engineered protein
« on: February 15, 2007, 04:12:52 PM »
I'm trying to figure this out.  I was given two graphs of an engineered protein and I'm suppose to explain what happened. 

First graph. 
X-axis pH
Y-Axis Log [H+/min]
Graph is a straight line with a positive slope. 

Second graph.
X-axis pH
Y-Axis total H+
Graph looks like a titration of an amino acid.  Starts low, Increases to a plateu that levels out then increase to another plateu.

The rate was monitored for the initial 5 minutes using acetic anhydride for the first graph and the total number of protons formed in 30 minutes is recorded for the second graph.  No numerical values are given.


I figured since acetic anhydride is pulling protons off of my protein they are coming off at a constant rate, raising the pH.  I thought there could be lysine or serine groups exposed to the acetic anhydride and these could be what donates the protons.  I also thought the acetic anhydride caused a conformational change in the protein and possible exposed the hydrophobic region. 

Is my thinking correct or is there something I'm missing?

Offline Yggdrasil

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Re: properties of an engineered protein
« Reply #1 on: February 15, 2007, 07:00:56 PM »
Is the protein an enzyme?  Is the H+ a product (or byproduct) of the reaction catalyzed by the enzyme?

Offline yolop

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Re: properties of an engineered protein
« Reply #2 on: February 15, 2007, 08:45:23 PM »
I'm assuming the H+ produced is a by product and is contributing to the increase in pH. 

If it was an enzyme would it make a difference?
Assuming it's NOT an enzyme would I be on track or should I look deeper into the structure or more general as just a protein with unknown composition?

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