D-mannose + GDP + H(+) => GDP-alpha-D-mannose + H2O
d-mannose + gdp + h(+) => gdp-alpha-d-mannose + h2o
D-mannose + GDP + H(+) => GDP-alpha-D-mannose + H2O
d-mannose + gdp + h(+) => gdp-alpha-d-mannose + h2o