摘要:

In investigations of radiolabeling substance P1–11(SP) with 125I isotope, its [Tyr8]-derivative was subjected to the lactoperoxidase (LPO) technique, whereas the native substance P undecapeptide was coupled with 125I-tyrosin-N-hydroxy-succinimidyl ester to the corresponding 125I-Bolton-Hunter SP derivative. For separation of the desired components from their by-products, labeled [Tyr8]-SP was pre-purified by ion-exchange chromatography (IEC) on carboxymethyl cellulose and subsequently investigated by gradient high performance reversed-phase liquid chromatography (gRP-HPLC) with 0.1 M triethyl-ammonium phosphate in acetonitrile (pH 2.5) on an octadecylsilyl silica gel (RP-18) stationary phase. When the total amount of labeled peptide affording a specific activity of approx. 2 × 106 Ci/M was checked by gRP-HPLC, the LPO technique yields about an equimolar mixture of 125I-[Tyr8]-(Met11)-SP and 125I-[Tyr8]-(Met11O)-SP. However, in contrast, substantial enrichment of 125I-[Tyr8]-(Met11)-SP was observed when more retained IEC fractions were analyzed.

ISSN:1082-6076    

DOI:10.1080/10826079808006599

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The advantages of the use of HPLC for the purification of the activated chloroplast F1ATPase, for the measurement of enzymatic activity (by ADP-ATP separation on anion exchange column) and for ATP binding measurement (by the Hummel and Dreyer chromatographic method on gel filtration columns) are pointed out, by comparison with conventional methods such as ATP regenerating method or centrifugation on Sephadex columns.

ISSN:1082-6076    

DOI:10.1080/10826079808006600

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Structural and surface properties of seven chromatographic silica gels were characterized by means of nitrogen adsorption and high-resolution thermogravimetry. The retention of alkyl benzenes was measured using the corresponding commercial octyl-bonded phases. The partition-displacement model was used to evaluate the equilibrium sorption constant and the surface excess of acetonitrile for each octyl phase. Most of the stationary phases studied showed similar sorption properties and, consequently, comparable values of the acetonitrile surface excess. Only for one of the phases studied the surface excess was much higher, and that was attributed to the difference in the silanol coverage of the stationary phase.

ISSN:1082-6076    

DOI:10.1080/10826079808006601

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A comprehensive analysis of multidetector size exclusion chromatography (SEC) is presented. The system examined consists of differential refractometer, capillary viscometer, and light-scattering detector combination. New approaches for interpreting multidetector data have been developed. The first one consists in eliminating the concentration chromatogram from the data reduction process. The traces of two molecular-weight-sensitive detectors alone allow calculating molecular weight and intrinsic viscosity distributions of an unknown polymer, assuming the validity of the universal calibration concept for this polymer. This approach can dramatically improve the characterization of polymers with long high-molecular-weight tails, when small amounts of high-molecular-weight fractions are detected by the light-scattering and viscometer detectors, but the concentration is too low to be registered by the refractometer.

ISSN:1082-6076    

DOI:10.1080/10826079808006602

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The retentions of 72 substituted N-benzylideneanilines (NBA) in normal phase liquid chromatography were determined using seven eluents prepared with heptan, tetrahydrofuran, octanol-1, and ethyl acetate. Principal component analysis (PCA) and correspondence factor analysis (CFA) were applied to describe the behavior of the compounds. With PCA, only one factor is necessary to model the retention. CFA offers an analysis of second-order effects and shows how the retention of the relevant compounds is related to the electronic effects. A multilinear regression with the Hammett's constants of substituents is established. The influence of the substituent position on retention is discussed.

ISSN:1082-6076    

DOI:10.1080/10826079808006603

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Sub-isoforms of rabbit liver metallothionein (MT-RL) and of its two main isoforms (RL-1 and RL-2) have been readily separated at room temperature on a reverse phase column using a gradient of TFA and acetonitrile. MT samples were prepared at neutral and acidic pH. The detection was double, consisting of two UV and electrochemical (EC) detectors on line, the EC (coulometric) detection being based on the oxidation of the thiol groups into disulphides at the graphite electrode. Two types of peaks were observed, those equally detected by UV and by EC, being attributed to original thiol containing sub-isoforms and those less hydrophobic, detected by UV but hardly at all by EC, being attributed to oxidised species containing disulphides instead of thiols, hence not detectable in our EC mode. All peaks in RL could be attributed to either RL-1 or RL-2 contribution, except for one of the oxidised forms. The elutions were then carried out at various temperatures between 25 and 60C.

ISSN:1082-6076    

DOI:10.1080/10826079808006604

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper describes high performance liquid chromatography (HPLC) conditions suitable for separating hydroperoxy-phospholipids from hydroxy-phospholipids. 1-stearoyl-2-(13-hydroperoxy-cis-9,trans-11-octadecadienoyl)-L-3-phosphatidyl-choline, 1, 2 di (13-hydroperoxy-cis-9,trans-11-octadecadienoyl)-L-3-phosphatidylcholine, 1-palmitoyl-2-(13-hydroperoxy-cis-9,trans-11-octadecadienoyl)-L-3-phosphatidylethan-olamine and their corresponding hydroxy-phospholipid derivatives were resolved by HPLC on an Ultracarb 5 ODS (20) column at 30C. Each pair of these phospholipids required different conditions for optimal separation but all used a mobile phase of acetonitrile-methanol-water mixture containing 10 mM choline chloride. The separation described allows accurate measurement of phospholipid hydroperoxide peroxidase activities.

ISSN:1082-6076    

DOI:10.1080/10826079808006605

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Aliphatic mono and dicarboxylic acids have been separated on silica-based ion-exchangers under conditions commonly used in ion-exclusion chromatography. Various retention mechanisms including ion-exclusion, hydrophobic interaction, and adsorption are involved in the separation of these analytes. The contribution of each of these mechanisms can be manipulated by varying the characteristics of the chromatographic support like exchange capacity or type of the spacer molecule used for the binding of the sulfonate groups to the silica. Thereby, fine-tuning of the separation selectivity is possible.

ISSN:1082-6076    

DOI:10.1080/10826079808006606

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:1082-6076    

DOI:10.1080/10826079808006607

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:1082-6076    

DOI:10.1080/10826079808006608

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor