Abstract
Phosphoenolpyruvate carboxykinase (PEPCK) undergoes light- or diurnally-regulated changes in phosphorylation in C3 and CAM plants but only in some C4 plants. The characteristics of this phosphorylation of PEPCK and its possible regulatory significance are discussed. The molecular mass of PEPCK from C4 plants is often smaller, and more variable, than the molecular mass of the enzyme in C3 and CAM plants. These differences probably reflect differences in the size of the N-terminal extension found in the enzyme from higher plants. This N-terminal extension contains the phosphorylation site and it is readily cleaved following extraction. PEPCK has four well-defined roles in plants: in photosynthesis in C4 and CAM plants, in the CO2-concentrating mechanism of certain algae and in gluconeogenesis following germination of fat-storing seedlings, but it has now also been located in the trichomes and in the phloem of some plants, such as cucurbits, suggesting a larger number of roles in plant metabolism than has hitherto been recognised. These possible roles are discussed, and in particular we discuss the general role of the phloem elements in cucurbits.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
