发信人: ucdavis (no), 信区: Biology
标 题: Re: his-tag蛋白提纯中,equlibrium buffer中的NaCl干什么
发信站: The unknown SPACE (Sat Nov 30 00:13:07 2002) WWW-POST

My answer for your reference.
Proteins and column both have charges.
Proteins can bind to the column by electrostatic interaction (so-called
non-specific binding). Of course this is not what you expect.
Assume Protein 1 is what you want, protein 2 is impurity.
If there is sodium chloride in the solution, sodium or chloride ion can
compete
with proteins to bind to column. So protein 2 will be removed from the column.
Although protein 1 is also decreased, the specific binding between histadine
and Ni is more important than electrostatic interaction. So protein1 can still
bind to column.
In brief, sodium chloride can prevent other proteins from binding to the
column to improve purity .Your target protein can still bind to the column by
forming complex between histadine and Ni.



【 在 elva (nothing really matters..) 的大作中提到: 】
: adding NaCl is to prevent the non-specific binding of protein to your
: Ni-column.
:
:
: 【 在 ucdavis (no) 的大作中提到: 】
: : What is your column? pH? is there DNA in your solution?
: :
: : 【 在 Rizhard (快乐的狗) 的大作中提到: 】
: : : 书上说at least NaCl 300mM, prevent ionic interaction,
: : : 到底是prevent什么ion和什么ion的interaction啊?
: : : 不加行不行啊?
: : :
: :
: :
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