pulse-chase studies show that this system is similar to the hela cell system in that both proteins are synthesized first as membrane-bound proteins of approximately 98 and 108 kda carrying asparagine-linked sugar side chains and are subsequently processed into higher molecular mass forms by the attachment of sulfate , phosphate , and further sugar groups including sialic acid , adding approximately 20 kda in apparent molecular mass .
C0033684
proteins
C0025252
membrane