 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Natural Science Forum / Chemistry / Organic Synthesis / July 2003I need some help
Sorry I don't know if I should be posting this in a technical forum... Anyway, I need to make a solution using a proteasome inhibitor (Carbobenzoxy-L-isoleucyl-(gamma)-t-butyl-L-glutamyl-L-alanyl-L-leucinal. Z-Ile-Glu(OBut)-Ala-Leu-H (aldehyde).)It's a Cell-permeable inhibitor of the multicatalytic proteinase complex Proteasome in HT4 cells. I want to create a vehicle using Propylene Glycol 50%, Deionized Water 20%, and Ethanol 30%. However, because the PSI compound has been lyophilized as an amorphous powder from DMSO solution I'm worried that my vehicle may cause the compound to racemize. The undissolved peptide is stable below -20C. Once prepared with the vehicle would it be stable at room temp? Anyone know?  SignaturePaul J. Franklin(moderator - sci.chem.organic.synthesis) http://organicworldwide.net/sci.chem.organic.synthesis Georgia State University <chepjf@panther.gsu.edu> Atlanta, GA > Sorry I don't know if I should be posting this in a technical forum... > Anyway, I need to make a solution using a proteasome inhibitor > (Carbobenzoxy-L-isoleucyl-(gamma)-t-butyl-L-glutamyl-L-alanyl-L-leucinal. > Z-Ile-Glu(OBut)-Ala-Leu-H (aldehyde).)It's a Cell-permeable inhibitor > of the multicatalytic proteinase complex Proteasome in HT4 cells. > I want to create a vehicle using Propylene Glycol 50%, Deionized Water > 20%, and Ethanol 30%. However, because the PSI compound has been > lyophilized as an amorphous powder from DMSO solution I'm worried that > my vehicle may cause the compound to racemize. The undissolved peptide > is stable below -20C. Once prepared with the vehicle would it be > stable at room temp? Lyophilized from DMSO? Either somebody was very good indeed or somebody is lying. How much DMSO is still in the powder? What is the optical rotation of the peptide? See if you can jury rig an optical rotation measurement from a solution-filled melting point capillary. Either have microscope cover slips for Super Glued windows, or glue in an optical fiber on each end to seal the filled capillary. Get the real world answer. (Not so hard: Monochromatic LED light (disassembled laser pointer, pick your color) in through an optical fiber, past a linear polarizer (careful here if it is a laser diode source), through the cap, past a second rotated polarizer to give minimal tranmission, then to a snugged photodiode and a meter. If the stuff racemizes the transmission increases. Control the temp. Take an occasional reading over time. Continuous is bad. Why?) SignatureUncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) "Quis custodiet ipsos custodes?" The Net! -- Paul J. Franklin(moderator - sci.chem.organic.synthesis) http://organicworldwide.net/sci.chem.organic.synthesis Georgia State University <chepjf@panther.gsu.edu> Atlanta, GA Uncle Al <UncleAl0@hate.spam.net> wrote: >Lyophilized from DMSO? Either somebody was very good indeed or >somebody is lying. Strange but true - DMSO can be removed by lyophilization. I didn't believe it at first either. Steve Turner Real address contains worldnet instead of spamnet SignaturePaul J. Franklin(moderator - sci.chem.organic.synthesis) http://organicworldwide.net/sci.chem.organic.synthesis Georgia State University <chepjf@panther.gsu.edu> Atlanta, GA |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2009 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.