Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A unique combination of chromatographic separation and mass spectrometric techniques has been developed for a novel method for measurement of picomole amounts of endogenous oligopeptides in biologic tissue. High-performance liquid chromatography is utilized for rapid high-resolution separation of peptides. A new buffer system using dilute triethylamine-formic acid is utilized. The buffer system possesses excellent UV transparent properties enabling femtomole sensitivity for measurement of standard solutions of somatostatin. Use of porous polystyrenedivinylbenzene copolymer and octadecylsilyl columns facilitate retention of a peptide fraction from biologic extracts. Advantage was taken of field desorption mass spectrometric methods to eliminate chemical derivatization of peptides and to produce protonated molecular ions which retain total molecular information of the peptide. Use of appropriate internal standards and selected ion monitoring methods enabled nanogram sensitivity and, more importantly, optimized structural specificity of the compound being quantified. Results are compatible with radioimmunoassay data. Data obtained with field desorption mass spectrometry provide, for the first time, measurement of intact, chemically underivatized oligopeptides extracted form biologic matrices and significantly, provide and analytic method to calibrate radioimmunoassay data. This novel combination of methods is being applied to measurements of peptide (leu-enkephalin, met-enkephalin, somatostatin, etc.) in canine brain regions and dental pulp tissue.
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PMID:High-performance liquid chromatographic and field desorption mass spectrometric measurement of picomole amounts of endogenous neuropeptides in biologic tissue. 732 Jan 15

The recent worldwide shortage of acetonitrile has prompted interest in alternative solvents for liquid chromatography/mass spectrometry (LC/MS). In this work, acetone was substituted for acetonitrile in the separation of a peptide mixture by reversed-phase high-performance liquid chromatography (RP-HPLC) and in the positive electrospray ionization mass spectrometry (ESI-MS) of individual peptides. On both C12 and C18 stationary phases, the substitution of acetone for acetonitrile as the organic component of the mobile phase did not alter the gradient elution order of a five-peptide retention standard, but did increase peak width, shorten retention times, and increase peak tailing. Positive ESI mass spectra were obtained for angiotensin I, bradykinin, [Leu(5)]-enkephalin, and somatostatin 14 dissolved in both acetonitrile/water/formic acid (25%/75%/0.1%) and acetone/water/formic acid (25%/75%/0.1%). Under optimized ESI-MS conditions, the mass spectral response of [Leu(5)]-enkephalin was increased two-fold when the solvent contained acetone. The substitution of acetone for acetonitrile resulted in only slight changes in the responses of the remaining peptides. A higher capillary voltage was required for optimum response when acetone was used. Compared with acetonitrile/water/formic acid (50/50/0.1%), more interfering species below m/z = 140 were found in the ESI-MS spectra of acetone/water/formic acid (50/50/0.1%).
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PMID:The use of acetone as a substitute for acetonitrile in analysis of peptides by liquid chromatography/electrospray ionization mass spectrometry. 1995 95