CBQCA assay of primary amine losses during hemodialysis.
AuthorsKirschbaum B
JournalClin Chim Acta
PubMed ID11412827
Nitrogen loss during hemodialysis is an important issue since all steps taken to improve clearance of urea will also increase loss of amino acids and other normally recyclable sources of nitrogen. Most dialyzers exclude albumin and other proteins, which react well with dyes commonly employed to measure protein, but do ... More
Facile synthesis of multivalent nitrilotriacetic acid (NTA) and NTA conjugates for analytical and drug delivery applications.
AuthorsHuang Z, Park JI, Watson DS, Hwang P, Szoka FC
JournalBioconjug Chem
PubMed ID17105240
'High-affinity nitrilotriacetic acids (NTA) have great potential in the molecular manipulation of His-tagged proteins. We have developed a facile method to synthesize multivalent NTA and its conjugates. Starting with appropriately protected lysine, we synthesized the mono-NTA synthons functionalized with either an amino group or a carboxylic group. We then obtained ... More
Evaluation of silica resins for direct and efficient extraction of DNA from complex biological matrices in a miniaturized format.
AuthorsTian H, Hühmer AF, Landers JP
JournalAnal Biochem
PubMed ID10906238
'For DNA purification to be functionally integrated into the microchip for high-throughput DNA analysis, a miniaturized purification process must be developed that can be easily adapted to the microchip format. In this study, we evaluate the effectiveness of a variety of silica resins for miniaturized DNA purification and gauge the ... More
Quantitation of protein.
AuthorsNoble JE, Bailey MJ,
JournalMethods Enzymol
PubMed ID19892168
The measurement of protein concentration in an aqueous sample is an important assay in biochemistry research and development labs for applications ranging from enzymatic studies to providing data for biopharmaceutical lot release. Spectrophotometric protein quantitation assays are methods that use UV and visible spectroscopy to rapidly determine the concentration of ... More
A comparison of protein quantitation assays for biopharmaceutical applications.
AuthorsNoble JE, Knight AE, Reason AJ, Di Matola A, Bailey MJ,
JournalMol Biotechnol
PubMed ID17914170
Dye-based protein determination assays are widely used to estimate protein concentration, however various reports suggest that the response is dependent on the composition and sequence of the protein, limiting confidence in the resulting concentration estimates. In this study a diverse set of model proteins representing various sizes of protein and ... More
Separation of free amino acids in human plasma by capillary electrophoresis with laser induced fluorescence: potential for emergency diagnosis of inborn errors of metabolism.
AuthorsBoulat O, McLaren DG, Arriaga EA, Chen DD
JournalJ Chromatogr B Biomed Sci Appl
PubMed ID11318418
Free amino acids (AAs) in human plasma are derivatized with 3-(4-carboxybenzoyl)quinoline-2-carboxaldehyde (CBQCA) and analyzed by capillary electrophoresis (CE) with laser induced fluorescence (LIF) detection. The labeling procedure is significantly improved over results reported previously. Derivatization can be completed in 40 min, with concentrations as low as 4 x 10(-8) M ... More
3-(4-Carboxybenzoyl)quinoline-2-carboxaldehyde, a reagent with broad dynamic range for the assay of proteins and lipoproteins in solution.
AuthorsYou WW, Haugland RP, Ryan DK, Haugland RP
JournalAnal Biochem
PubMed ID9025944
This paper describes the application of 3-(4-carboxybenzoyl)quinoline-2-carboxaldehyde (CBQCA), a sensitive fluorogenic reagent for detection of amines, to the assay of proteins in solution. The sensitivity and dynamic range of CBQCA in the determination of protein concentration is modulated by the number of accessible amines present in the protein assayed. Thus, ... More
Helical interactions and membrane disposition of the 16-kDa proteolipid subunit of the vacuolar H(+)-ATPase analyzed by cysteine replacement mutagenesis.
Theoretical mechanisms of proton translocation by the vacuolar H(+)-ATPase require that a transmembrane acidic residue of the multicopy 16-kDa proteolipid subunit be exposed at the exterior surface of the membrane sector of the enzyme, contacting the lipid phase. However, structural support for this theoretical mechanism is lacking. To address this, ... More
Direct fluorescent staining and analysis of proteins on microspheres using CBQCA.
AuthorsGraves SW, Woods TA, Kim H, Nolan JP
JournalCytometry A
PubMed ID15812850
BACKGROUND: General methods for accurate determination of microsphere surface protein loading are needed for applications from protein arrays to molecular assembly studies. Current methods include bulk absorption measurements of stained microspheres or use of known fluorescently tagged binding partners, which limit sensitivity and general applicability, respectively. METHODS: Microspheres bearing covalently ... More
Transbilayer peptide sorting between raft and nonraft bilayers: comparisons of detergent extraction and confocal microscopy.
AuthorsVidal A, McIntosh TJ
JournalBiophys J
PubMed ID15908585
Membrane microdomains ("rafts") that sequester specific proteins and lipids are often characterized by their resistance to detergent extraction. Because rafts are enriched in sphingomyelin and cholesterol, raft bilayers are thicker and have larger area compressibility moduli than nonraft bilayers. It has been postulated that rafts concentrate proteins with long transmembrane ... More
Sorting of lipids and transmembrane peptides between detergent-soluble bilayers and detergent-resistant rafts.
AuthorsMcIntosh TJ, Vidal A, Simon SA
JournalBiophys J
PubMed ID12944280
Specific proteins and lipids sequester to regions of cell membranes called rafts. Due to their high content of sphingomyelin (SM) and cholesterol, raft bilayers are thicker than nonraft bilayers and, at least at 4 degrees C, are resistant to Triton X-100 extraction. It has been postulated that rafts concentrate proteins ... More