Posts in ABRF Discussion Forum

-----Original Message-----
From: ABRF Discussion Forum <email obscured>> On Behalf Of ken.schoppmann
Sent: Wednesday, August 5, 2020 2:04 PM
To: <email obscured>
Subject: [ABRF Discussion Forum] New content in JBT now available




The latest issue of the Journal of Biomolecular Techniques is now available
online, along with Early Access articles for the upcoming issue.

Visit www.jbt.abrf.org to explore the full issue.



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-----Original Message-----
To: <email obscured> <email obscured>>
Sent: Wed, Aug 5, 2020 11:09 am
Subject: Re: [ABRF Discussion Forum] New content in JBT now available

Ken,Thank you very much.  I have been trying for years to get such
announcements started!Stay well,Ron

Ronald L. Niece, Ph.D.Research Resources & Technologies
Tustin CA 92782 USACA Phone 714-508-7503CA FAX 714-508-9587

-----Original Message-----
From: ken.schoppmann <email obscured>>
To: <email obscured>
Sent: Wed, Aug 5, 2020 11:03 am
Subject: [ABRF Discussion Forum] New content in JBT now available




The latest issue of the Journal of Biomolecular Techniques is now available
online, along with Early Access articles for the upcoming issue.

Visit www.jbt.abrf.org to explore the full issue.



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-----Original Message-----
From: ABRF Discussion Forum <email obscured>> On Behalf Of Kym Faull
Sent: Tuesday, August 4, 2020 11:07 AM
To: <email obscured>
Subject: [ABRF Discussion Forum] Collagen solubility

Does anyone know about the solubility characteristics of collagen.  According
to information on the internet it is insoluble in water, and the solubility is
increased in aqueous acid.  We would like to know if it dissolves in chaotropic
reagents such as 6M guanidine HCl or urea

Kym
Kym Francis Faull, Ph.D.
Director, Pasarow Mass Spectrometry Laboratory Jane and Terry Semel Institute
for Neuroscience and Human Behavior at UCLA Professor Emeritus, Department of
Psychiatry and Biobehavioral Sciences David Geffen School of Medicine at UCLA
Telephone: (310) 206 7881 (office)
Telephone: (310) 206 7886 (laboratory)
Facsimile: (310) 206 2161
Electronic mail: <email obscured> <email obscured>>








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Cheers

W

-----Original Message-----
From: ABRF Discussion Forum <email obscured>] On Behalf Of J. Will
Thompson, Ph.D.
Sent: Tuesday, August 4, 2020 8:25 AM
To: <email obscured>
Subject: Re: [ABRF Discussion Forum] Changing charge state distributions on a
small molecule

Hi Kym

Post-column addition of DMSO (we use a 10% by volume flow of 50/50 DMSO/MeCN,
to add 5% DMSO by volume) seems to heavily shift to lower charge states in our
hands.  This has not been tremendously helpful for many small molecules yet;
I've tested several applications without benefit, but we don't have many small
molecules with multiple charge states.  It sounds like you might have a nice
application.  We use this routinely for peptides, as has been described
extensively at low-flow but not discussed much at microflow/analytical flow
(which is what we are doing).

Cheers

Will

-----Original Message-----
From: ABRF Discussion Forum <email obscured>] On Behalf Of matt
sweeney
Sent: Monday, August 3, 2020 9:01 PM
To: <email obscured>
Subject: Re: [ABRF Discussion Forum] Changing charge state distributions on a
small molecule

Kym
I would say you can shift it in liquid phase or after its desolvation.

In Liquid you would have to shift solution pH. More basic. Fewer protons to chg
that amine. The quat nitrogen is a done deal. Its charged. That might mess with
your chromatography system by shifting to basic conditions. So you could try to
add a liquid post column containing ammonium hydroxide. With a T or using a
sheath liquid system like the older Thermo highish flow sources had. You might
need decent amounts of base.

In the case of already sprayed ions one can attempt charge stripping by
increasing desolvation energy. Temperature and tuning can be adjusted perhaps
to knock off that ‘extra’ proton on the non-tertiary amine. One often risks
fragmenting the single charge species when attempting to knock off this proton
with heat or tuning values. One must balance things. It can be helpful to play
around a bit and see.

Since this is often desired as part of improving detection sensitivity under
ms/ms or srm one might just monitor both ions and fragments. Sum the signals.
Save the trouble of playing around. Or just monitor one. You might not get much
for all the hassle.

Matt from phone

> On Aug 3, 2020, at 5:13 PM, Kym Faull <email obscured>> wrote:
>
> We have a molecule of molecular weight around 750. It has a quaternary
nitrogen plus some other primary amino functions..  On reversed phase in 0.1 %
formic acid eluates (water and acetonitrile) it is detected as a singly charged
ion and a doubly charged ion in relative intensities of around 60/40,
respectively.  Is there some easy way to drive the ionization to all or mostly
one charged state or the other?  Any and all advice will be appreciated.
>
> Kym
>
>
>
> Kym Francis Faull, Ph.D.
> Director, Pasarow Mass Spectrometry Laboratory Jane and Terry Semel
> Institute for Neuroscience and Human Behavior at UCLA Professor
> Emeritus, Department of Psychiatry and Biobehavioral Sciences David
> Geffen School of Medicine at UCLA
> Telephone: (310) 206 7881 (office)
> Telephone: (310) 206 7886 (laboratory)
> Facsimile: (310) 206 2161
> Electronic mail: <email obscured> <email obscured>>
>
>
>
>
>
>
>
>
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>
> Kym
>
>
>
> Kym Francis Faull, Ph.D.
> Director, Pasarow Mass Spectrometry Laboratory
> Jane and Terry Semel Institute for Neuroscience and Human Behavior at UCLA
> Professor Emeritus, Department of Psychiatry and Biobehavioral Sciences
> David Geffen School of Medicine at UCLA
> Telephone: (310) 206 7881 (office)
> Telephone: (310) 206 7886 (laboratory)
> Facsimile: (310) 206 2161
> Electronic mail: <email obscured> <email obscured>>
>
>
>
>
>
>
>
>
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-----Original Message-----
From: ABRF Discussion Forum <email obscured>> On Behalf Of turck
Sent: Saturday, July 25, 2020 4:00 AM
To: <email obscured>
Subject: Re: [ABRF Discussion Forum] looking for peptides with phosphorylated
His

Hi Andy, we are not in the pHis synthesis business anymore. We worked on it
quite a bit while I was at UCSF. Check out our paper on synthesis and mass spec
analysis: 10.1002/pro.5560060704 Maybe you can just get the "naked" peptide and
do postsynthesis histidine-phosphorylation reaction with potassium
phosphoramidate. It is fairly simple.

Peptides were synthesized using the Fmoc chemistry. After cleavage and
deprotection, the peptides were purified by RP-HPLC and lyophilized. Peptide
identity was confirmed by mass spectrometry. For phosphorylation, 0.5 mg of
the deprotected  and lyophilized peptide was dissolved in  10 mM ammonium
bicarbonate  and the pH was adjusted to
8 with 0.1 M  NaOH. Ten milligrams  of potassium phosphoramidate were added and
the mixture was tumbled overnight at  room temperature. Purification  of  the
peptides  was  performed  on  a Vydac pH-stable reversed-phase column (The
Separations Group, Hesperia, California) using 10 mM ammonium bicarbonate as
solvent A and  acetonitrile/lO mM ammonium  bicarbonate  (9:l)  as solvent B. A
linear  gradient  was  applied,  increasing  solvent  B concentration from 0%
to 35% over 60 min at a flow  rate of 0.5 mL/min. Peptides were detected at 215
nm and 280 nm. The eluted peptides were stored in solution at 4°C.
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