Purification, properties and partial amino-acid sequence of 1-aminocyclopropane-1-carboxylic acid oxidase from apple fruits.
The enzyme which converts 1-aminocyclopropane-1-carboxylic acid (ACC) into ethylene, ACC oxidase, has been isolated from apple fruits (Malus x domestica Borkh. cv. Golden Delicious), and for the first time stabilized in vitro by 1,10-phenanthroline and purified 170-fold to homogeneity in a five-step procedure. The sodium dodecyl sulfate-denatured and native proteins have similar molecular weights (approx. 40 kDa) indicating that the enzyme is active in its monomeric form. Antibodies raised against a recombinant ACC oxidase over-produced in Escherichia coli from a tomato cDNA recognise the apple-fruit enzyme with high specificity in both crude extracts and purified form. Glycosylation appears to be absent because of (i) the lack of reactivity towards a mixture of seven different biotinylated lectins and (ii) the absence of N-linked substitution at a potential glycosylation site, in a sequenced peptide. Phenylhydrazine and 2-methyl-1-2-dipyridyl propane do not inhibit activity, indicating that ACC oxidase is not a prosthetic-heme iron protein. The partial amino-acid sequence of the native protein has strong homology to the predicted protein of a tomato fruit cDNA demonstrated to encode ACC oxidase.
Dupille
E
E
ENSAT, Toulouse, France.
Rombaldi
C
C
Lelièvre
J M
JM
Cleyet-Marel
J C
JC
Pech
J C
JC
Latché
A
A
D000594:Amino Acid Oxidoreductases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D000595:Amino Acid Sequence; D005638:Fruit / Q000201:enzymology* / Q000235:genetics; D007700:Kinetics; D008969:Molecular Sequence Data
D000594:Amino Acid Oxidoreductases; C059460:1-aminocyclopropane-1-carboxylic acid oxidase