Phosphoenolpyruvate synthase/pyruvate phosphate dikinase [Carbohydrate transport and metabolism]

phosphoenolpyruvate synthase. Also called pyruvate,water dikinase and PEP synthase. The member from Methanococcus jannaschii contains a large intein. This enzyme generates phosphoenolpyruvate (PEP) from pyruvate, hydrolyzing ATP to AMP and releasing inorganic phosphate in the process. The enzyme shows extensive homology to other enzymes that use PEP as substrate or product. This enzyme may provide PEP for gluconeogenesis, for PTS-type carbohydrate transport systems, or for other processes [Energy metabolism, Glycolysis/gluconeogenesis].

phosphoenolpyruvate synthase; Validated

Phosphoglucan water dikinase (also known as alpha-glucan water dikinase), N-terminal CBM20 (carbohydrate-binding module, family 20) domain. This domain is found in the chloroplast-encoded phosphoglucan water dikinase, one of two enzymes involved in the phosphorylation of plant starches. In addition to the CBM20 domain, phosphoglucan water dikinase contains a C-terminal pyruvate binding domain. The CBM20 domain is found in a large number of starch degrading enzymes including alpha-amylase, beta-amylase, glucoamylase, and CGTase (cyclodextrin glucanotransferase). CBM20 is also present in proteins that have a regulatory role in starch metabolism in plants (e.g. alpha-amylase) or glycogen metabolism in mammals (e.g. laforin). CBM20 folds as an antiparallel beta-barrel structure with two starch binding sites. These two sites are thought to differ functionally with site 1 acting as the initial starch recognition site and site 2 involved in the specific recognition of appropriate regions of starch.

Pyruvate phosphate dikinase, PEP/pyruvate binding domain. This enzyme catalyzes the reversible conversion of ATP to AMP, pyrophosphate and phosphoenolpyruvate (PEP).