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31st July 2014 @ 11:54

Update Nov 16th 2014 - results obtained from Pfizer:

Results of Series 4 Aldehyde Oxidase Assay

Update Nov 16th 2014 - the compounds actually sent were as follows

Compounds sent for AO assay

AO Compounds Sent.png


Update 13th Aug 2014 (original post below)

Final compound list is this, with some reasons (following input from Paul Willis):

Aldehyde Oxidase Shortlist 2

Codes of compounds to be sent:


Plus ONE of these two, whichever has the most sample available:



Original Post:

Exciting news. We have a lab willing and able to run the aldehyde oxidase assay, and not just any lab but one of the experts in this field - Scott Obach’s lab at Pfizer, Groton.

(Interestingly Pfizer are the originators of the currently most active series in OSM, Series 4, on which this assay will be deployed).

Scott has previously published on the increasing profile of AO in drug discovery/development. Several Series 4 compounds have shown a susceptibility to metabolic clearance:

Metabolism ID Study for Three Triazolopyrazines

Physiochemical Evaluation and Metabolism of 8 Test Compounds in Human and Mouse Liver Microsomes

There’s a summary on the wiki of all the current metabolic data for this series.

One of the possible problems is that these molecules contain aza-aromatic structures able to be oxidized adjacent to the nitrogen atoms - that is, I believe, a known substrate for AO. If that’s happening the it’s something we can deal with - and was probably something that was briefly looked at in the original work, explaining the synthesis and evaluation of these analogs.

But before we worry too much, we should see if these compounds are substrates for this enzyme. Following our appeal for help, I contacted Scott to see if he’d be interested, and he is. Pfizer have agreed to this, and to be named as contributing to OSM in this way, which is fantastic.

The aim is to run the assay on a set of 6-12 molecules at the outset in a human cytosolic lability assay vs. positive controls to test for AO-mediated consumption (here's the general method). If we see activity and want to examine several compounds further, we could then look at a rodent AO assay, since there are known to be species differences. One step at a time.

Experimental data would allow a comparison with the predictive work performed by Chris Swain.

Scott took a look at the Series 4 wiki and chose the long list of molecules below. Only some of these are available: the list of current stocks is here. Paul Willis added MMV669784, which is available.

AO First Shortlist

So, question. We have space for up to 6 more structures. What should we include, and why? Scott needs 1-2 mg of each. Again, the full list of what’s known about Series 4 metabolism is here, and we’re already including/addressing the most interesting compounds I think.

Some other possibilities from Series 4 are these:

AO Assay Second Set of Possibles

The first two, MMV669846 and MMV670250 seem like obvious choices given their variation of the core heterocycle. MMV670946 is a surrogate for MMV670945 which was on the original list but is no longer available. MMV672727 might be interesting as an ether resistant to benzylic oxidation. We have no good structures containing aliphatic amines, as far as I can tell.

Are we light on the regular ethers, i.e. should we include one more compound analogous to MMV639565 or MMV670437? Maybe we provide one from newly-synthesised stocks in Sydney? Are there other interesting structures available that people feel might ask/answer interesting AO-related questions, particularly alterations in the core triazolopyrazine core?

On the other hand, could we also ship compounds from previous series, to answer questions there too, for publication purposes? (The Series 1 paper is an an advanced state of write-up).

To summarize: which other compounds should go into this assay? We have room for up to 6 more.

Deadline for decision: Morning of Wednesday August 6th 2014. Then we’ll ship.

Places for comments/suggestions: Below (login with Google account to comment) or Github or G+ or Twitter using @O_S_M or (last resort) email ( but please make it clear you’re happy to have comments relayed publicly with attribution.

(This post authored by Mat)

Linked Posts
Attached Files
AO Shortlist 1.png
Second Set of Possibles.png
List of Codes to Send.xlsx
AO Shortlist 2.cdxml
AO Shortlist 2.png
AO Compounds Sent.cdxml
AO Compounds Sent.png