the sialyltransferase assays consist of an enzyme source which is either the surface of intact cells ( ectoenzyme ) or a triton x-100 cell homogenate , the nucleotide sialic acid donor ( cytidine monophosphate-n-acetylneuraminic acid ) , and an asialo-acceptor which may be endogenous to the enzyme preparation or may be added exogenously .
C0699040
surface of
C0007634
cell