Primary structures of the alanine-rich antifreeze polypeptides from grubby sculpin, Myoxocephalus aenaeus

1988 ◽  
Vol 66 (2) ◽  
pp. 403-408 ◽  
Author(s):  
Avijit Chakrabartty ◽  
Choy L. Hew ◽  
Margaret Shears ◽  
Garth Fletcher
Keyword(s):  
Amino Acids ◽  
Molecular Size ◽  
Close Relative ◽  
Active Components ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Shorthorn Sculpin ◽  
Phase Liquid ◽  
Myoxocephalus Scorpius ◽  
Antifreeze Polypeptides

Antifreeze polypeptides (AFP) isolated from the plasma of the grubby sculpin (Myoxocephalus aenaeus)were compared with those of a close relative, the shorthorn sculpin (Myoxocephalus scorpius). Both species synthesize a family of AFP that are alanine rich and exist as amphiphilic α-helices. The grubby sculpin AFP could be resolved into five active components by reverse-phase liquid chromatography. The major (GS-5) and one of the minor (GS-8) components were sequenced. Grubby sculpin AFP GS-5 was 33 amino acids long. It was homologous to one of the minor shorthorn sculpin AFP (SS-3) in terms of its molecular size and amino acid sequence. The sequences of these two components differed by only four amino acids. The minor grubby sculpin AFP GS-8 was 40 amino acids long. It was shorter than the major shorthorn sculpin AFP (SS-8) by five amino acids. The sequence of the first 40 amino acids from SS-8 and GS-8 was essentially identical, differing by only 4 amino acids. Antibodies raised against SS-8 cross reacted with GS-8 but not with the shorter AFP (GS-5 and SS-3). The data suggest that the antibody was directed towards the unstructured N-terminal regions of SS-8 and GS-8. It would appear that shorthorn and grubby sculpins possess similar families of AFP genes and that the grubby sculpin preferentially expresses one gene product (GS-5) while the shorthorn sculpin expresses another, larger product (SS-8).

Quantitative Analysis of Methionine, Cysteine, and Lysine in Feeds by Reversephase Liquid Chromatography Using Precolumn Derivatization with 9- Fluorenylmethyl Chloroformate: Preliminary Study

1990 ◽  
Vol 73 (6) ◽  
pp. 935-939 ◽  
Author(s):  
Angel Cubedo Fernández-Trapiella
Keyword(s):  
Amino Acids ◽  
Liquid Chromatography ◽  
Quantitative Analysis ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Precolumn Derivatization ◽  
Fluorescence Detector ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Phase Liquid

Abstract An Improved analytical method based on precolumn derivatization with 9-fluorenylmethyl chloroformate (9-FMC) and reverse- phase liquid chromatography was developed for quantitative analysis of methionine, cysteine, and lysine In feeds. Samples of corn, whey powder, soybean meal, meat meal, and fish meal were selected for an accurate determination of these 3 amino acids. A portion of each finely ground sample was weighed and subjected to oxidation with performic acid for 16 h before hydrolysis with 6N HCI for 24 h. An aliquot of each hydrolysate was evaporated, dissolved, and diluted with 0.2M pH 7.85 borate buffer. An aliquot of each final solution was derlvatlzed with 9-FMC and analyzed by reverse- phase liquid chromatography using a fluorescence detector with a 254 nm excitation filter and a 313 nm emission filter. The 2 sulfur amino acids and lysine were perfectly separated from all other amino acids with a simple binary gradient. Cysteine (analyzed as cysteic acid), methionine (as methionine sulfone), and lysine were quantltated using internal standard calibration. Hydrolysates were also analyzed by conventional Ion-exchange chromatography (IEC). Amino acid values as obtained by the proposed LC method were close to IEC data. Considering IEC results as reference values, the differences In recovery of amino acids In feedstuffs determined by both methods were not more than 7.5%. Precision of the LC method was evaluated within a single hydrolysate and between different hydrolysates of a single sample. Coefficients of variation (CV) were not more than 4.1 and 5.9%, respectively.

Determination of Diacetyl in Butter as 2,3-Diaminonaphthalene Derivative, Using a Fluorometric Procedure or Reverse Phase Liquid Chromatography with Fluorescence Detection

1988 ◽  
Vol 71 (3) ◽  
pp. 462-465
Author(s):  
Pietro Damiani ◽  
Giovanni Burini
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
The Other ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Fluorescence Characteristics ◽  
Chromatographic Procedure ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Two procedures, one fluorometric and the other reverse phase liquid chromatographic, for determination of a derivative of diacetyl are described. Exploratory work on diacetyl standard solutions to establish the best conditions for the derivatization with 2,3-diaminonaphthalene (DAN) to yield 2,3-dimethylbenzo[g]-quinoxaline (DMBQ) is discussed, as well as the fluorescence characteristics of the DMBQ derivative. Diacetyl was determined in 10 commercial butter samples by the proposed procedures and by other known methods (determination of o-phenylenediamine and 3,3-diaminobenzidinederivatives). Recoveries from butter samples spiked with known amounts of diacetyl ranged from 96.9 to 101.8% (with CVs ranging from 0.3 to 2.1%) for the fluorometric procedure and from 96.9 to 102.7% (with CVs ranging from 0.5 to 2.4%) for the chromatographic procedure. These results agree well with those obtained with o-phenylenediamine and 3,3-diaminobenzidine methods on the same butter samples. The proposed methods have the advantages of improved detectability and specificity.

Determination of Aspirin and Salicylic Acid by Reverse-Phase Liquid Chromatography

1987 ◽  
Vol 70 (6) ◽  
pp. 964-966
Author(s):  
Dorothy R Heidemann ◽  
Edward S Schulenberg ◽  
William H Smith
Keyword(s):  
Salicylic Acid ◽  
Dosage Forms ◽  
Solid Dosage Forms ◽  
Reverse Phase ◽  
Solid Dosage ◽  
Reverse Phase Liquid Chromatography ◽  
Sample Extraction ◽  
Phase Liquid ◽  
Phase Column

Abstract Buffered solid dosage forms containing aspirin, magnesium hydroxide, and aluminum hydroxide are blended with acidic ethanol to extract the aspirin and salicylic acid rapidly. The resulting preparation is then immediately injected onto a 4.6 mm x 3 cm 5 (im reverse-phase column. Aspirin and free salicylic acid are determined simultaneously. The run time is <2 min. The total time from the initiation of sample extraction to completion of the separation is <5 min.

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