Open AccessPurification and Some Properties of 2‐Decylhomocitrate Synthase from Penicillium spiculisporum
Author(s) -
Måhlén Anders
Publication year - 1973
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1973.tb03029.x
Subject(s) - citrate synthase , enzyme , substrate (aquarium) , chemistry , atp synthase , peptide , biochemistry , non competitive inhibition , acetyl coa , penicillium , chromatography , stereochemistry , biology , food science , ecology
2‐Decylhomocitrate synthase, which catalyses the condensation between lauroyl‐CoA and 2‐oxoglutarate has been purified from Penicillium spiculisporum to a specific activity of 1.2μmol×min −1 ×mg −1 . It also accepts decanoyl‐CoA as substrate. The peptide chain weight is about 43000, and s 0 20,W for the native enzyme is 8.3 S. The apparent pH optimum is 8.3 and apparent K m values are for lauroyl‐CoA ≤ 1 μM at 3.3 mM oxoglutarate and for oxoglutarate, 0.75 mM at 28 μM lauroyl‐CoA. Oxaloacetate is an inhibitor competitive with oxoglutarate with K i of 0.4–0.8mM. Palmitoyl‐CoA is partially competitive with lauroyl‐CoA. 5,5′‐Dithiobis(2‐nitrobenzoic acid) inactivates the enzyme but this is partially prevented by lauroyl‐CoA or palmitoyl‐CoA, and strongly prevented by both substrates or combinations of substrate and inhibitor. Great similarities between this enzyme and 2‐decylcitrate synthase from another strain of the mold are found in kinetic behaviour, molecular size and SH sensitivity, but a preliminary peptide mapping experiment reveals considerable differences in their primary structure.