dol-P-Man:Man(1)GlcN-acyl-PI alpha-1,6-mannosyltransferase activity
dol-p-man:man(1)glcn-acyl-pi alpha-1,6-mannosyltransferase activity
Catalysis of the transfer of an alpha-D-mannosyl residue from dolichol-P-mannose to Man(1)-GlcN-acyl-PI, forming an alpha-(1->6)-D-mannosyl-D-mannose linkage. This transfers the second mannose to the GPI precursor.