[The degradation of glycoproteins with lithium borohydride. Isolation and analysis of O-glycopeptides with reduced C-terminal amino acid residue].
By the example of fetuin and a blood-group-specific mucin from porcine stomach, we showed that, under conditions of reductive degradation of glycoproteins with LiBH4-LiOH in 70% aqueous tert-butyl alcohol, the reduction and cleavage of amide bonds occur much faster than the simultaneous beta-elimination of carbohydrate chains O-linked with Ser and Thr residues of the peptide chain. The major degradation products containing the O-linked glycans are the O-glycosylated derivatives of 2-aminopropane-1,3-diol and 2-aminobutane-1,3-diol (the products of reduction of glycosylated Ser and Thr) and the glycopeptides containing 2-4 amino acid residues with reduced C-terminal amino acid. Seventeen homogeneous O-glycopeptides were isolated from the fetuin degradation products by ion-exchange and reversed-phase HPLC. Their structures were determined by MALDI-TOF mass spectrometry and by analyses for amino acids, amino alcohols, and carbohydrates. The application of the reaction for characterization of O-glycans and localization of O-glycosylation sites in O- and N,O-glycoproteins is discussed.
Arbatskiĭ
N P
NP
Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia.
Likhosherstov
L M
LM
Serebriakova
M V
MV
Brusov
O S
OS
Shibaev
V N
VN
Derevitskaia
V A
VA
Kochetkov
N K
NK
D000818:Animals; D001894:Borohydrides / Q000737:chemistry / Q000378:metabolism*; D006020:Glycopeptides / Q000737:chemistry / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D006031:Glycosylation; D018020:Lithium Compounds / Q000737:chemistry / Q000378:metabolism*; D009077:Mucins / Q000737:chemistry / Q000378:metabolism; D013552:Swine; D000509:alpha-Fetoproteins / Q000378:metabolism
D001894:Borohydrides; D006020:Glycopeptides; D006023:Glycoproteins; D018020:Lithium Compounds; D009077:Mucins; D000509:alpha-Fetoproteins; C040936:lithium borohydride