A. Geyer et al., Structure and characterization of the glycan moiety of L-amino-acid oxidase from the Malayan pit viper Calloselasma rhodostoma, EUR J BIOCH, 268(14), 2001, pp. 4044-4053
Ophidian L-amino-acid oxidase (L-amino-acid oxygen:oxidoreductase, deaminat
ing, EC 1.4.3.2) is found in the venom of many poisonous snakes (crotalids,
elapids and viperids). This FAD-dependent glycoprotein has been studied fr
om several snake species (e.g. Crotalus adamanteus, Crotalus atrox and Call
oselasma rhodostoma) in detail with regard to the biochemical and enzymatic
properties. The nature of glycosylation, however, as well as the chemical
structure(s) of the attached oligosaccharide(s) are unknown. In view of the
putative involvement of the glycan moiety in the biological effects of oph
idian L-amino-acid oxidase, notably the apoptotic activity of the enzyme, s
tructural knowledge is needed to evaluate its exact function. In this study
we report on the glycosylation Of L-amino-acid oxidase from the venom of t
he Malayan pit viper (Calloselasma rhodostoma). Its glycosylation is remark
ably homogenous with the major oligosaccharide accounting for approximately
90% of the total sugar content. Based on detailed analysis of the isolated
oligosaccharide by 2D NMR spectroscopies and MALDI-TOF mass spectrometry t
he glycan is identified as a bis-sialylated, biantennary, core-fucosylated
dodecasaccharide. The biological significance of this finding is discussed
in light of the biological activities of the enzyme.