Pectin methylesterase (PME)

Pectin methylesterase (PME) is a key enzyme responsible for the de-esterification of homogalacturonan (HG), the primary component of pectin in plant cell walls [1]. By removing methyl groups from the galacturonic acid residues, PME alters the charge and mechanical properties of the cell wall, facilitating either wall loosening or stiffening depending on the local environment [1, 4]. This activity is essential for fundamental plant processes such as cell growth, fruit ripening, and organ abscission [1]. In the context of plant pathology, PME is a major virulence factor for various fungi and bacteria that utilize the enzyme to degrade host tissues during infection [2]. Consequently, PME and its interaction with HG represent significant targets for agricultural biotechnology, particularly in developing disease-resistant crops and controlling fruit softening [2]. Small molecules like epigallocatechin gallate (EGCG) and endogenous protein inhibitors (PMEIs) are known to modulate PME activity, offering pathways for chemical and genetic intervention [3]. While not a traditional target for human therapeutics, PME-mediated modification of pectin is relevant to the food industry and the study of dietary fiber's impact on the human microbiome [4]. Sources: [1] Pelloux, J., et al. (2007). Pectin methylesterases: cell wall enzymes with important roles in plant development. Trends in Plant Science. [2] Lionetti, V., et al. (2012). Pectin-modifying enzymes at the interface between plant and pathogens. Frontiers in Plant Science. [3] Lewis, K. C., et al. (2008). Epigallocatechin gallate, a constituent of green tea, suppresses pectin methylesterase activity. Phytochemistry. [4] Micheli, F. (2001). Pectin methylesterases: cell wall enzymes with important roles in plant development. Trends in Plant Science.

Other names

Pectin esterasePectin demethoxylasePectin methoxylasePECarbohydrate esterase family 8

Catalyzes the de-esterification of pectin homogalacturonan, releasing methanol and protons, thereby altering cell wall porosity and mechanical properties.