Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatives of monosaccharides, maltooligosaccharides, and oligosaccharides enzymatically released from asparagine-linked sites in ribonuclease B and fetuin have been investigated using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Use of the matrix 2,6-dihydroxyacetophenone containing diammonium hydrogen citrate (DHAP/DAHC) resulted in predominance of protonated over sodiated pseudomolecular ions of PMP-derivatized oligosaccharides. By comparison, the matrices alpha-cyano-4-hydroxycinnamic acid and 2,5-dihydroxybenzoic acid resulted in predominantly sodiated pseudomolecular ions. In addition, tendencies for fragmentation of PMP-oligosaccharide derivatives were significantly lower with DHAP/DAHC which enabled meaningful data to be obtained in reflector mode, even for samples with high excipient levels. The relative magnitude of the ion signals for PMP-derivatized maltooligosaccharides and ribonuclease B oligosaccharides correlated well with the oligomer distribution apparent by HPLC. PMP-maltohexose was used as an internal standard to quantitate PMP-oligosaccharides from ribonuclease B and asialofetuin in crude derivatization mixtures. A linear relationship was observed between the ratio of the intensities of pseudomolecualr ions and the amount of glycoprotein derivatized. The limit of detection for the major oligosaccharide of each protein was reached with ca. 3 micrograms of glycoprotein but may be further enhanced by optimization of sample handling. PMP derivatives of sialylated fetuin oligosaccharides were readily detected as protonated pseudomolecular ions by linear mode analyses. By comparison, reflector mode analyses revealed substantially reduced magnitudes of protonated pseudomolecular ions and considerable post-source fragmentation of sialic acid residues. The PMP derivatives of fetuin oligosaccharides were also amenable to exoglycosidase treatment as shown by the mass shifts found upon treatment with sialidase.
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PMID:Oligosaccharide characterization and quantitation using 1-phenyl-3-methyl-5-pyrazolone derivatization and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. 917 25

The performance of the new ionic liquid MALDI-MS matrix 2,5-dihydroxybenzoic acid butylamine (DHBB) was assessed and compared to results obtained with the ionic liquid MALDI-MS matrixes alpha-cyano-4-hydroxycinnamic acid butylamine (CHCAB), 3,5-dimethoxycinnamic acid triethylamine (SinTri), and the frequently used solid MALDI matrixes 2,5-dihydroxybenzoic acid (DHB) and alpha-cyano-4-hydroxycinnamic acid (CHCA). The vacuum-stable, liquid consistency of ionic liquid matrix sample preparations considerably enhanced MALDI-MS analysis in terms of shot-to-shot reproducibility. Consequently, relative standard deviations serving as a measure for reproducibility of intensity-values acquired from 90 different spots on one MALDI-MS preparation were approximately one-half as high when solid DHB was replaced by the ionic liquid DHBB and eight times lower after exchange of solid CHCA by ionic liquid CHCAB. Interestingly, the ionic liquid MALDI matrix DHBB conserved the broad applicability of its solid analogue DHB, reduced MALDI induced fragmentation of monosialylated glycans and gangliosides, and was the superior ionic liquid matrix for MALDI-MS analysis of oligosaccharides and polymers, such as poly(ethylene glycol). It also worked well with glycoconjugates, peptides, and proteins; however, the tendency of DHBB to form multiple alkali adduct ions with peptides and proteins made CHCAB the ionic liquid matrix of choice for peptides. SinTri was the best ionic liquid matrix for proteins of high molecular weight, such as IgG. Furthermore, it was demonstrated for the first time that solvent properties and MALDI matrix properties of ionic liquids, such as DHBB, can be combined to enable fast, direct screening of an enzymatic reaction. This was proven by the desialylation of sialylactose with sialidase from Clostridium perfringens in the presence of diluted aqueous DHBB and subsequent direct MALDI-MS analysis of the reaction mixture.
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PMID:2,5-Dihydroxybenzoic acid butylamine and other ionic liquid matrixes for enhanced MALDI-MS analysis of biomolecules. 1514 8