
TY  - JOUR
A1  - Milborrow, B.V. 
A1  - Lee, H.-S. 
T1  - Endogenous biosynthetic precursors of (+)-abscisic acid. VI. Carotenoids and ABA are formed by the &#8216;non-mevalonate&#8217; triose-pyruvate pathway in chloroplasts
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 1998
VL  - 25
IS  - 5
SP  - 507
EP  - 512
KW  - abscisic acid; triose-pyruvate pathway; non-mevalonate biosynthesis; cell-free system; chloroplasts; IDP.
UR  - https://doi.org/10.1071/PP98006 
N2  - A cell-free system from avocado fruit which routinely incorporated &#91;14C&#93;mevalonate into ABA (1000 dpm per 5 mL of preparation), and into carotenoids, has now been shown to incorporate &#91;14C&#93;pyruvate even more successfully (1620 dpm). Intact chloroplasts from spinach leaf protoplasts incorporated 2990 dpm of &#91;14C&#93;pyruvate (from 2 x 106 dpm) into ABA compared with 990 dpm from &#91;3-R-5-14C&#93;mevalonate (also from 2 x 106 dpm). The intact chloroplasts also produced &#91;14C&#93;ABA (1575 dpm) when supplied with &#91;14C&#93;isopentenyl diphosphate. This result establishes that the whole pathway of biosynthesis of ABA can occur within chloroplasts. Little &#91;14C&#93;acetate or &#91;14C&#93;alanine was incorporated into ABA by avocado fruit mesocarp. Most of the ABA in leaf tissue now appears to be formed by the triose-pyruvate pathway in chloroplasts and incorporation of &#91;14C&#93;mevalonate occurs after activation in the cytoplasm and importation of a later intermediate into the plastids. 
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