Biology-Online • View topic - Western Blot Protein Length
Advertisement
Advertisement

## Western Blot Protein Length

Genetics as it applies to evolution, molecular biology, and medical aspects.

Moderator: BioTeam

### Western Blot Protein Length

Hello Forum,

please take a look at this image

http://imageshack.us/photo/my-images/98/0bigg.jpg/

It shows a Western blot of an extract of proteins.

My question is how can you determine the length of both proteins A and B graphically?

Could you please help me?
rayman
Garter

Posts: 5
Joined: Tue Aug 30, 2011 12:17 pm

the mobility (expressed as distance of band from the start) is proportional to log M_r
So, if you want to have it precise, measure distances from start to respective bands, calculate log of their molecular weight and put into graph. By calculating the equation, you can calculate M_r of your proteins
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

JackBean
Inland Taipan

Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm

### Re: Western Blot Protein Length

Thank you for your answer.

I have some questions left.

What do you mean by M_r ?

How can I put them into the graph? What is the equation?
rayman
Garter

Posts: 5
Joined: Tue Aug 30, 2011 12:17 pm

M_r is the molecular mass (or relative weight, that's the same, except units)

on x-axis you put log M_r; on y-axis you put the distance and let the Excel calculate the equation
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

JackBean
Inland Taipan

Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm

### Re: Western Blot Protein Length

Thank you for your answer.

I need help with Excel.

Can you tell me what I have to type in?

Do you use any kind of messengers so I can ask you in a faster way?
rayman
Garter

Posts: 5
Joined: Tue Aug 30, 2011 12:17 pm

### Re: Western Blot Protein Length

Why do I have to use the log of MW ?
rayman
Garter

Posts: 5
Joined: Tue Aug 30, 2011 12:17 pm

because otherwise you would have logaritmic line, what is not that big problem today, since we use computers anyway, but using log is kind of more convenient
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

JackBean
Inland Taipan

Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm

### Re: Western Blot Protein Length

Thank you.

I read on other websites that there is another way to solve this.

They basically follow the same procedure but instead of only measuring the distance from the starting point they divide the length of the protein by the distance from the starting point.

So you have another coordinate system with the log(MW) on the x-axis and the division of distance over length on the y-axis.

Which way do you recommend? Yours or the above mentioned?
rayman
Garter

Posts: 5
Joined: Tue Aug 30, 2011 12:17 pm

what is length of protein? Like 35 kDa/5 cm?
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

JackBean
Inland Taipan

Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm

i suppose teh corner shop was fresh out of common sense...
merv
Death Adder

Posts: 58
Joined: Sun Oct 02, 2011 2:05 pm

Return to Genetics

### Who is online

Users browsing this forum: No registered users and 1 guest