Amos,
For the uninitiated among us (especially me!!) can you give a brief
description of HILIC?
Thanks,
Derek Bradley
Dept. of Medicine
UCL
London
At 12:22 22/02/01 Thursday, Amos Heckendorf wrote:
>Len
>
>Thank you for the posting. It is always entertaining to have a major
>marketing company admit some limits. Do you think that they will now come
>out with a product for crow, having acquired a good taste of it here?
>
>Dr. Alpert and I have posted several times on the use of HILIC for
>detergent removal, as well as for phosphopeptide retention, rather than
>the IMAC approach. However, there has not been much feedback on this
>subject. I am curious as to whether anyone has had success with
>this? (One underutilized function of this discussion group would be to
>allow more manufacturer postings so that the free market of ideas would
>more quickly move us onto better products or techniques. We have to agree
>to be civil about it though!)
>
>Part of the problem with the HILIC approach is that the salt
>concentrations are somewhat high in in-gel digests and one needs to
>carefully manage this aspect of the problem so that the polar peptides
>will actually stick. Keeping the molarity below 50mM is only a benchmark
>level. It may require even less salt present, so a C18 step is not out of
>the question here, but the salt tolerance of HILIC methods needs to be
>better defined.
>
>Additionally the capacity of ZipTips or their competitors (PrepTips and
>SuproTips) are somewhat low as compared to MiniSpin columns with HILIC
>chemistries. The liquid volumes of spin columns are not substantially
>larger than the coated wall or plugged flow tips, but the bed volumes are
>much greater. This means that the amount of polar solute retained could be
>greater, and you would not need as clean a sample to be successful at this.
>
>We have samples of both types of products available for those of you
>interested in framing this problem in more realistic terms other than the
>standards that have been run. Please let me know if you are interested.
>
>I hope to see many of you at San Diego where we can discuss this further.
>
>Sincerely,
>Amos Heckendorf (amos@nestgrp.com)
>508.481.6223
>
>----------
>>I am forwarding some feedback from Millipore, vendors of ZipTip, on the
>>recent IMAC ZipTip discussion as I think our members would be interested
>>to read them.
>>
>>
>>----------
>>
>>Hi Len:
>>
>> I've been watching your messages on the newsgroup and have a few
>> comments. I am the inventor of ZipTip and am responsible for new product
>> development. The introduction of ZipTipMC for phosphopeptides was a
>> balancing act. After reading the literature on the use of IMAC for
>> phosphopeptides, it was clear that scientists were quite split on
>> whether it really worked. However, for those who managed to get the
>> chemistry to work, it was quite beneficial, because there was no other
>> easy way. When we launched the product, we knew that it was not going to
>> work for all sequences and hence we put the disclaimers in the operating
>> instructions. Nonetheless, we felt that the product could provide a
>> useful tool to some customers. This was a risky decision because it
>> balanced the possibility of helping a portion of our customers while
>> potentially upsetting others- - -possibly to the detriment of the ZipTip
>> reputation.
>>
>> Looking back, if I had to do it all over, I would probably still [have]
>> launched it. The reason is that we have helped a few labs to advance
>> their research. Fundamentally, having IMAC in a ZipTip is a good idea,
>> if just to have the chemistry capability. However, from a product
>> introduction standpoint, it really helps to have an application that
>> scientists can relate to, hence phosphopeptides.
>>
>> The issue that we are encountering is that there are others like
>> yourself that are not having good luck with the IMAC chemistry in this
>> application. For this, I would like to personally apologize for any
>> inconvenience that this has caused. I hope that the explanation above
>> explains our reasoning.
>>
>>Millipore
>>
>>----------
>>
>>
>>You need not offer apologies. I was one of the researchers pressing
>>Millipore to make IMAC ZipTips as it is a potentially useful tool for
>>those of us who do not have the benefits of triple quads. However, as
>>you say it is not an easy science and for some is already proving
>>its worth. Are you continuing to investigate this product in terms of
>>exploring different chemistries or applicability to different types
>>of phosphorylated sequences (rather than just beta-casein)?
>>Len
>>
>>
>>Regarding additional investigation of the IMAC chemistry, with the
>>exception of a few low key outside collaborations, we've probably closed
>>the book on this chapter. Although the subtleties of sequence/PO4 as it
>>relates to IMAC binding would be a fascinating graduate research project,
>>unfortunately its not something that I can pursue at this time.
>>
>>Lastly, if you are going to ABRF (I won't be attending), I would like to
>>invite you to view our poster on hydrophilic interaction chromatography.
>>ZipTips with this chemistry were shown to very effective for removing
>>detergents and stains from peptides.
>>
>>Millipore
>>
>>----------
>>
>>--
>>*********************************************************************
>>Dr Len C. Packman
>>Assistant Director of Research
>>Protein and Nucleic Acid Chemistry Facility
>>Department of Biochemistry
>>University of Cambridge
>>80 Tennis Court Road
>>Old Addenbrookes Site
>>Cambridge, CB2 1GA, UK
>>Tel: +44 (1223) 333639
>>FAX: +44 (1223) 766002
>>e-mail: lcp2@mole.bio.cam.ac.uk
>>Visit my WWW page at http://www.bio.cam.ac.uk/proj/adr/PNAC/pnac.html
>
>--
>Amos Heckendorf, Ph.D. (amos@nestgrp.com)
>
>The Nest Group, Inc., Value Added Resellers of HPLC Columns (VydacÅ,
>PolyLCÅ, Jordi-GelÅ, Macherey-Nagel NucleogenÅ, Higgins Analytical HAISilÅ
>LS, TARGAÅ & CLIPEUSÅ, and Nest Group MACCELÅ) SAI flash chromatography
>cartridges; and AmiKa Harvard Bioscience BioDialyserÅ, Dispo-BioDialyserÅ
>, 96-Well Dialysis Plates, and SuproTipÅ MS MicroSample SPE Tips.
>
>Tel: 800-347-6378 or 508-481-6223; FAX 508-485-5736;
>45 Valley Rd, Southboro, MA 01772-1306
>Applications and Protocols at our NEW site:
>http://www.nestgrp.com/protocols/protocol.shtml
>
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