McGinnis K, Ku G M, Fu J, Stern A M, Friedman P A
Merck Research Laboratories, West Point, PA 19486, USA.
Biochim Biophys Acta. 1998 Sep 8;1387(1-2):454-6. doi: 10.1016/s0167-4838(98)00130-7.
In previous chemical modification studies on bovine aspartyl (asparaginyl) beta-hydroxylase, cysteines were implicated as critical catalytic residues. Using site-directed mutagenesis, the five cysteine residues located in a highly conserved region of the enzyme identified as the active site were individually mutated to alanine. Substitutions at cysteine 637, 644, 656, 681, and 696 resulted in active mutant enzymes indicating that these residues are not required for catalysis.
