GDP Mannose Pyrophosphorylase A (GMPPA)

GMPPA is thought to encode a GDP-mannose pyrophosphorylase. This enzyme catalyzes the reaction which converts mannose-1-phosphate and GTP to GDP-mannose which is involved in the production of N-linked oligosaccharides.GDP-mannose pyrophosphorylase (GMPP) catalyses the synthesis of GDP-mannose, which is the precursor for the mannose residues in glycoconjugates, using mannose 1-phosphate and GTP as substrates. Repression of GMPP in yeast leads to phenotypes including cell lysis, defective cell wall, and failure of polarized growth and cell separation. A prerequisite for the synthesis of these molecules is the availability of the activated mannose donor, GDP-Man, the product of the catalysis of mannose-1-phosphate and GTP by GDP-mannose pyrophosphorylase (GDP-MP).