Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0393754 (HSA)
 2,996 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A high-performance liquid chromatographic method for the simultaneous determination of 5-aminosalicylic acid (5-ASA), acetyl-5-aminosalicylic acid (Ac-5-ASA) and 2,5-dihydroxybenzoic acid (5-HSA) in human endoscopic intestinal biopsy with electrochemical detection has been developed and validated. A liquid-liquid extraction procedure was used to isolate these drugs from the biological material prior to analysis. The compounds were separated on an Erbasil S reversed-phase column using methanol-critic acid-sodium hydrogenphosphate-heptane-sulfonic acid-disodium ethylenediaminetetraacetate (pH 3) as mobile phase. The method was linear from 1.0 to 300 ng ml-1 for 5-ASA, from 10 to 1000 ng ml-1 for Ac-5ASA and from 0.1 to 10 ng m-1 for 5-HSA. The limit of detection for 5-ASA and for Ac-5-ASA was 1 ng ml-1 and that for 5-HSA was 0.1 ng ml-1. This procedure is suitable for pharmacological and clinical studies of 5-ASA.
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PMID:Simultaneous determination of 5-aminosalicylic acid, acetyl-5-aminosalicylic acid and 2,5-dihydroxybenzoic acid in endoscopic intestinal biopsy samples in humans by high-performance liquid chromatography with electrochemical detection. 883 80

Several approaches were explored for obtaining high sequence coverage in protein modification studies performed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Human serum albumin (HSA, 66.5kDa) was used as a model protein for this work. Experimental factors considered in this study included the type of matrix used for MALDI-TOF MS, the protein digestion method, and the use of fractionation for peptide digests prior to MALDI-TOF MS analysis. A mixture of alpha-cyano-4-hydroxycinnamic acid and 2,5-dihydroxybenzoic acid was employed as the final matrix for HSA. When used with a tryptic digest, this gave unique information on only half of the peptides in the primary structure of HSA. However, the combined use of three enzyme digests based on trypsin, endoproteinase Lys-C, and endoproteinase Glu-C increased this sequence coverage to 72.8%. The use of a ZipTip column to fractionate peptides in these digests prior to analysis increased the sequence coverage to 97.4%. These conditions made it possible to examine unique peptides from nearly all of the structure of HSA and to identify specific modifications to this protein (e.g., glycation sites). For instance, Lys199 was confirmed as a glycation site on normal HSA, whereas Lys536 and Lys389 were identified as additional modification sites on minimally glycated HSA.
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PMID:Obtaining high sequence coverage in matrix-assisted laser desorption time-of-flight mass spectrometry for studies of protein modification: analysis of human serum albumin as a model. 1635 58