I still have not receive any answer about "molecular biological
experimental design" and what it has to do with purifying proteins. Is
there a connection. I just want to know what is about. Can it help me
with purifying proteins or understanding purifying proteins. This is
my second time ashing you. Please help.

                             Ted.

The study and manipulation of proteins falls within the realm of
molecular biology.  Molecular biology is an experimental science. 
"Good" experiments, that is, ones that are likely to result in the
discovery of new knowledge, generally follow from a good experimental
design.

To answer your question, if an experiment is to be conducted that is
intended to result in the purification of a protein, then having a
good experimental design is vitally important.

If an established process is to be used to purify a protein, this is
not an experiment, and the term "experimental design" is not
applicable.

Maybe nobody knows what you are talking about.

The question is too open ended for a specific answer.  Or if you
really want the answer.

According to Webster - 
design - A basic scheme or pattern that affects and controls function
or development
experimental - Of the nature of an experiment; constituting or undergoing a test
biological - Having to do with biology
molecular - Of, relating to, or consisting of molecular

Given this "molecular biological experimental design" is the scheme or
pattern of processes of a experiment working with molecules of
biological significance.   A protein is a biological molecule.
So to purify a protein and you can't buy a coffee filter that can
purify it for you - you may have to experiment for a while to develop
a process to purify the protein.

Since you have to ask this question - we can tell you are a long way
from purifying proteins.

Now a piece of advice for tedmccall-ga.

1)  When asking a question make certain it is specific.  Frame you
question in such a way that an unambiguous answer can be given in
response.  You will avoid alot of follow-on questions and get an
answer that makes since.

2)  STOP WRITING IN ALL CAPITAL LETTERS.  THIS IS EQUIVALENT TO YELLING.

Now a piece of advice to xarqi-ga.

Dude - tm-ga is either a lawyer, kid, or a guy with a book of
molecular biology patents.

As for experimental design not being applicable to protein
purification - i'll remember that next time I design a high-yield
process to generate the human fibronection from e. coli in
bio-reactors you are going to need to activate your t-killer cell
response and i have to run through all the 50 parameters
experimentally available to turn on 5 kg/day.

And I'll just return my paycheck also while I'm at it.

Thanks for the info, drimagine.

Note though that my comment stated that experimental design was not a
part of "an established process".  The scenario you describe is
clearly one for which the optimal parameters have yet to be
determined.  The quest to determine these would likely entail many
experiments, hopefully with good design.  If you are just using a
shot-gun method to tweak a system with 50 unknowns and hoping for the
best, that is cookery, not science.

xarqi-ga
    I'm not trying to tweak your nose but -- I didn'r realize we were
talking SCIENCE not science.
I'll remember that the next time I pick up my paycheck - and will be more humble.

Whether I'm building a proton-anti-proton collider and looking for W
particle decay,  observing planetary motion and back calculating the
the deviations between Newtonian mechanics and General Relativity,
running a reaction to develop bi-molecular platinum (III) complexes,
or investigating the remodeling process of stem cells injected into
scarred myocardium, intelligent experimental design is an
indisguishable part of good "Science".   If the investigator does not
specifically control for all the biases or outside interactions that
can affect the result of the experiment then any science that is done
is serendipity not the control or experiment of the investigator.   My
experience is that you learn much more by having the experiment go
wrong the first few times than you have by everything going right.  
However you have to work much harder for that understanding.
It is much easier to be lucky that to be smart.

As for a system with 50 unknowns - of course one doesn't perform a
simplex operation to find the optimum - only a person with a boring
and unnaturally long life would chose that path.  However the problem
I described is real and is not just a scale-up process.   Ask your
friendly chemical engineer about scaling up any laboratory reaction to
a plant size operation and you'll find out a lot of science wasn't
performed in the lab since all the side reactions where so small at
the milli-gram level that no one bothered to work them out.

Again, I'm not being insulting but there is much to investigating any
phenomena that involves good experimental design.