title: Carbohydrate composition of Carcinus aestuarii hemocyanin.
abstract: The hemocyanin of the crab Carcinus aestuarii contains a carbohydrate moiety that represents 1.6% of protein mass. This carbohydrate content is higher than that exhibited by other arthropod hemocyanins so far investigated. By combination of FPLC ion exchange chromatography and reverse-phase HPLC, the native oligomeric protein can be resolved into three major and one minor electrophoretically pure fractions that are found to be homogeneous by N-terminal sequencing and correspond to the subunit polypeptide chains. Sugar analysis on the different subunits reveals that the subunit referred to as Ca2 is glycosylated, with a carbohydrate content of 6.3%. By Ca2 trypsin digestion, separation of glycopeptides, and amino acid sequencing, three consensus sequences for O-glycosylation and one for N-glycosylation were found. MALDI-MS was applied for the determination of the molecular masses of the various glycopeptides and peptides after removal of carbohydrates by neuraminidase and alpha-N-acetylgalactosaminidase.
authors.affiliation: Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia, 1113, Bulgaria. pda54@hotmail.com
authors.forename: P
authors.initials: P
authors.lastname: Dolashka-Angelova
authors.forename: M
authors.initials: M
authors.lastname: Beltramini
authors.forename: A
authors.initials: A
authors.lastname: Dolashki
authors.forename: B
authors.initials: B
authors.lastname: Salvato
authors.forename: R
authors.initials: R
authors.lastname: Hristova
authors.forename: W
authors.initials: W
authors.lastname: Voelter
mesh_terms: D000818:Animals; D003386:Brachyura / Q000737:chemistry*; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D006020:Glycopeptides / Q000737:chemistry / Q000302:isolation & purification; D006031:Glycosylation; D006433:Hemocyanins / Q000737:chemistry*; D006596:Hexosaminidases; D008969:Molecular Sequence Data; D015394:Molecular Structure; D008970:Molecular Weight; D009439:Neuraminidase; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D048809:alpha-N-Acetylgalactosaminidase
chemical_list: D002241:Carbohydrates; D006020:Glycopeptides; D010446:Peptide Fragments; D006433:Hemocyanins; D006596:Hexosaminidases; D009439:Neuraminidase; D048809:alpha-N-Acetylgalactosaminidase