Re: extinction coefficient
Dr. Ming F. Tam (MBR405@ccvax.sinica.edu.tw)
Fri, 10 Jul 1998 13:16:37 +0800
>Date: Fri, 10 Jul 1998 13:13:11 +0800
>To: JohnNakamura@inhale.com
>From: "Dr. Ming F. Tam" <MBR405@ccvax.sinica.edu.tw>
>Subject: Re: extinction coefficient
>Cc:
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>>A well characterized protein with known molecular weight has a defined
>>extinction coefficient for quantitating protein amount by UV analysis.
>>However, when the protein is lyophilized, the gravimetric weight of the
>>lyophilized material is much higher by about 20% than the value calculated
>>from UV analysis. This preparation is also extremely pure which excludes
>>impurities contributing to the overall weight. What can be happening and
>>how would you test your hypothesis?
>
>
Your sample probably has salt contributed by the buffer. Lyophilize same
volume of buffer as your sample and see how much salts you have.
*********************************
Dr. Ming F. Tam
mbr405@ccvax.sinica.edu.tw
Institute of Molecular Biology
Academia Sinica
Nankang, Taipei 11529
Taiwan, ROC
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