Exploring the catalytic mechanism of skeletal muscle UDP-glucose pyrophosphorylase: identification of a hyperreactive cysteine at the enzyme active site.
1. The involvement of cysteine residues in the catalytic mechanism of UDP-glucose pyrophosphorylase was suggested by the rapid inactivation of the enzyme by N-ethylmaleimide, even at 1:1 reagent/enzyme stoichiometric ratios. 2. The inactivation is largely prevented by uridine substrates (UDP-glucose and UTP) in agreement with the assumption that the reactive cysteine is located at the active site.
Bergamini
C M
CM
Istituto di Chimica Biologica dell'Università, Ferrara, Italia.
Signorini
M
M
D000818:Animals; D001665:Binding Sites; D003545:Cysteine / Q000378:metabolism*; D007700:Kinetics; D009132:Muscles / Q000201:enzymology*; D011817:Rabbits; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase / Q000378:metabolism*
D005957:UTP-Glucose-1-Phosphate Uridylyltransferase; D003545:Cysteine