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Purification and characterization of pumpkin long‐chain acyl‐CoA oxidase
Author(s) -
De Bellis Luigi,
Giuntini Pietro,
Hayashi Hiroshi,
Hayashi Makoto,
Nishimura Mikio
Publication year - 1999
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1999.106204.x
Subject(s) - biochemistry , acyl coa , enzyme , chemistry , substrate (aquarium) , substrate specificity , stereochemistry , biology , ecology
Pumpkin ( Cucurbita sp.) long‐chain acyl‐CoA oxidase (ACOX) (EC 1.3.3.6) was purified to homogeneity by hydrophobic interaction, hydroxyapatite, affinity, and anion exchange chromatographies. The purified isoenzyme is a dimeric protein, consisting of two apparently identical 72‐kDa subunits. The protein is exclusively localized in glyoxysomes. The enzyme catalyzes selectively the oxidation of CoA esters of fatty acids with 12–18 C atoms and exhibits highest activity with C‐14 fatty acids, but no activity with isobutyryl‐CoA and isovaleryl‐CoA (branched chain) or glutaryl‐CoA (dicarboxylic). The enzyme is strongly inhibited by high concentrations of palmitoyl‐CoA and weakly inhibited by high concentration of myristoyl‐CoA. It is also inhibited by Triton X‐100 at concentrations above 0.018% (w/v) the critical micellar concentration. The consequences of the substrate inhibition for the evaluation of long‐chain ACOX activity in plant tissues are discussed.