mb-3 (drug) mb-3 (drug) mb-3 is a drug which acts as a potent and selective inhibitor of the histone acetyltransferase enzyme gcn5, which usually functions as a negative modulator of pgc-1α, and so mb-3 acts to indirectly activate pgc-1α. it is used in research into the role of the gcn5/pgc-1α pathway in the regulation of metabolism and cell differentiation. mb-3 (drug)identifiers iupac name (2r,3s)-4-methylidene-5-oxo-2-propyloxolane-3-carboxylic acid pubchem cid21579153chemical and physical dataformulac9h12o4molar mass184.191 g·mol−13d model (jsmol)interactive image smiles ccc1(c(=c)c(=o)o1)c(=o)o inchi inchi=1s/c9h12o4/c1-3-4-6-7(8(10)11)5(2)9(12)13-6/h6-7h,2-4h2,1h3,(h,10,11)/t6-,7+/m1/s1key:srqutzjzabszrq-rqjhmyqmsa-n