dephytylated

Dephytylated describes a molecule from which the phytyl (phytol) side chain has been removed. The phytyl group is a long hydrophobic diterpene chain commonly attached to chlorophyll and related pigments via an ester linkage. Dephytylation thus refers to the hydrolytic cleavage of this ester bond, yielding a phytyl-free core molecule such as chlorophyllide and free phytol.

In chlorophyll metabolism, dephytylation is a key step in both biosynthesis and degradation. Enzymatic dephytylation is carried out by chlorophyll dephytylases or related hydrolases, which remove the phytol tail to produce chlorophyllide. This reaction can occur during leaf senescence, fruit ripening, or other physiological or environmental conditions that promote chlorophyll turnover. Non-enzymatic dephytylation can also occur under certain conditions, such as oxidative stress or high light, though it tends to be less controlled and slower.

Beyond chlorophyll, the term can apply to the dephytylation of other phytylated compounds where a phytol-like side chain is attached to a molecular scaffold. However, chlorophyll and its immediate degradation intermediates are the most studied examples, and dephytylation is most commonly discussed in the context of pigment catabolism and salvage pathways.

Significance lies in altering solubility, localization, and downstream metabolism of the core molecule. The liberated phytol can be recycled into isoprenoid biosynthesis, while the dephytylated product enters further steps of pigment breakdown or remodeling. Dephytylation thus contributes to pigment turnover, nutrient recycling, and plant responses to developmental cues and stress.