di-trans,octa-cis-undecaprenyl phosphate + GDP-alpha-D-mannose <=> D-mannosyl di-trans,octa-cis-undecaprenyl phosphate + GDP
di-trans,octa-cis-undecaprenyl phosphate + gdp-alpha-d-mannose <=> d-mannosyl di-trans,octa-cis-undecaprenyl phosphate + gdp