ISSN:
1432-2048
Keywords:
Key words: Acyl-acyl carrier protein thioesterase
;
Fatty acid synthetase II
;
Helianthus (seed)
;
β-keto-acyl-acyl carrier protein synthetase II
;
Mutant fatty acid
;
Palmitic acid
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract. Two high-palmitic acid sunflower (Helianthus annuus L.) mutants, CAS-5 and CAS-12, have been biochemically characterised. The enzymatic activities found to be responsible for the mutant characteristics are β-keto-acyl-acyl carrier protein synthetase II (KASII; EC 2.3.1.41) and acyl-acyl carrier protein thioesterase (EC 3.1.2.14). Our data suggest that the high-palmitic acid phenotype observed in both mutant lines is due to the combined effect of a lower KASII activity and a higher thioesterase activity with respect to palmitoyl-acyl carrier protein (16:0-ACP). The level of the latter enzyme appeared to be insufficient to hydrolyse the produced 16:0-ACP completely. As a consequence of this, three new fatty acids appear: palmitoleic acid (16:1 Δ9), asclepic acid (18:1 Δ11), and palmitolinoleic acid (16:2 Δ9 Δ12). These fatty acids should be synthesised from palmitoyl-ACP or a derivative by the action of the stearoyl-ACP desaturase, fatty acid synthetase II and oleoyl-phosphatidylcholine desaturase, respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004250050514
