β-carboline alkaloids as matrices for UV-matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in positive and negative ion modes. Analysis of proteins of high molecular mass, and of cyclic and acyclic oligosaccharides

We report that commercially available β-carbolines (nor-harmane (9H-pyrido[3,4-b]indole), harmane (1-methyl-9H-pyrido[3,4-b]indole), harmine (7-methoxy-1-methyl-9H-pyrido[3,4-b]indole), harmol (1-methyl-9H-pyrido[3,4-b]indol-7-d]), harmaline (3,4-dihydro-7-methoxy-1-methyl-9H-pyrido[3,4-b]indole) an...

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Detalles Bibliográficos
Autores principales: Nonami, H., Tanaka, K., Fukuyama, Y., Erra-Balsells, R.
Formato: JOUR
Materias:
carboline derivative
oligosaccharide
protein
article
chemistry
laser
mass spectrometry
molecular weight
ultraviolet radiation
Carbolines
Lasers
Molecular Weight
Oligosaccharides
Proteins
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Ultraviolet Rays
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_09514198_v12_n6_p285_Nonami
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
Descripción
Sumario:We report that commercially available β-carbolines (nor-harmane (9H-pyrido[3,4-b]indole), harmane (1-methyl-9H-pyrido[3,4-b]indole), harmine (7-methoxy-1-methyl-9H-pyrido[3,4-b]indole), harmol (1-methyl-9H-pyrido[3,4-b]indol-7-d]), harmaline (3,4-dihydro-7-methoxy-1-methyl-9H-pyrido[3,4-b]indole) and harmalol (3-4-dihydro-1-methyl-9H-pyrido[3,4-b]indol-7-ol)), are useful MALDI matrices at 337 nm, for cyclic oligosaccharides (cyclodextrins, range 972-1290 Da), acyclic oligosaccharides (range 342-828 Da) and high molecular mass proteins (range 23 290-66 525 Da) in both positive and negative modes. This was investigated by using time-of-flight (TOF) mass spectrometers of different sensitivities, equipped with and without pulse extraction facilities. A comparison with conventional matrices for carbohydrates (DHB and DHB/HIC) indicates that β-carbolines provide the same level of sensitivity and resolution in the positive mode, but offer the advantage of high levels of sensitivity and resolution in the negative mode. Harmaline has been found to be specially effective for the analysis of high-mass proteins in both modes, and also exhibits excellent experimental reproducibility of the results owing to the homogeneous crystallization of the analyte-matrix mixture over the entire sample surface area. Harmane and nor-harmane are both excellent matrices for high-mass proteins also. As MALDI matrices, β-carbolines permit measurement of sulfated sugars in the negative ion mode as ([M-H]), and of neutral sugars and proteins as both [M+U]+ and [M-H]- in appropriate modes.

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