Hi Steve, With my experience, it is (very) common to see AMPPNP is hydrolyzed to AMPPN (supposedly) with my protein. Although the literature often reported AMPPNP as a stable ATP mimic, such a luck wasn't true with my case, maybe same as you. If you go to Sigma website where I purchased, it may say it is not stable in an acidic condition. My mother liquor was in an acidic condition. So you'd better consider if you used it in an acidic condition, otherwise, your protein inherently has a strong power to hydrolyze it. In addition to the pH, I often see it can go hydrolysis easily. However, you can try more as you mentioned it may contain impurity. I just want to inform you that it is not surprising to see this hydrolysis.
Good luck~ Young-Jin On Mon, Feb 14, 2011 at 8:30 AM, Soisson, Stephen M < stephen_sois...@merck.com> wrote: > Hi there, > > Was recently looking at a structure of an enzyme with AMP-PNP added to the > crystallization mix, and all I see is density for ADP. I was wondering if > hydrolysis of AMP-PNP to ADP is relatively common - either as a result of > extended time in crystallization or exposure of the resultant crystals to > synchrotron radiation? > > I know that there can be up to 10% contamination of ADP in the purchased > material, so it could just be that we have selected that form in the > crystal, or that there was endogenous ADP bound that failed to substitute. > Just curious if hydrolysis is a common observation. > > Thanks in advance- > > Steve > > Stephen M. Soisson, Ph.D. > *Structural Chemistry Site Lead, WP* > > Merck Research Laboratories > 770 Sumneytown Pike, WP14-1101 > West Point, PA 19486 > Phone: (215) 652-6185 > Fax: (215) 652-9051 > stephen_sois...@merck.com > > Notice: This e-mail message, together with any attachments, contains > information of Merck & Co., Inc. (One Merck Drive, Whitehouse Station, > New Jersey, USA 08889), and/or its affiliates Direct contact information > for affiliates is available at http://www.merck.com/contact/contacts.html) > that may be confidential, > proprietary copyrighted and/or legally privileged. It is intended solely > for the use of the individual or entity named on this message. If you are > not the intended recipient, and have received this message in error, > please notify us immediately by reply e-mail and then delete it from > your system. > >
