scholarly journals Photoaffinity labelling of cyanomethaemoglobin with derivatives of tryptophan and 5-bromotryptophan

1995 ◽  
Vol 308 (1) ◽  
pp. 251-260 ◽  
Author(s):  
M Li ◽  
Z Lin ◽  
M E Johnson
Keyword(s):  
Amino Acid ◽  
Binding Sites ◽  
Tryptic Peptide ◽  
Fast Atom Bombardment ◽  
Binding Mode ◽  
Reversed Phase ◽  
Reversed Phase Hplc ◽  
Photoaffinity Labelling ◽  
Derivatives Of ◽  
Fast Atom Bombardment Ms

Tryptophan and 5-bromotryptophan (5-BrTrp) are relatively potent inhibitors of sickle-haemoglobin polymerization. The binding sites of these compounds to normal and sickle haemoglobin (HBA and HBS) have been suggested, but not firmly established, through the use of spin-labelled derivatives and/or computer modeling. In the present study we approached the problem by utilizing the technique of photoaffinity labelling. The cyanomet forms of HBA and HBS were subjected to photoaffinity labelling with N alpha-(4-azidotetrafluorobenzoyl)tryptophan and N alpha-(1-ethyl-2-diazomalonyl)-5-bromotryptophan respectively. Both irradiated samples of HBA and HBS were denatured, digested with trypsin, and then separated by reversed-phase HPLC. A labelled tryptic peptide was isolated from the photolabelling of HBS with N alpha-(1-ethyl-2-diazomalonyl)-5-bromotryptophan. The peptide was identified to be Val1(alpha)-Lys7(alpha), with the label attached to Val1(alpha), by virtue of amino acid analysis and sequencing, in conjunction with fast-atom-bombardment MS. The binding mode of N alpha-(1-ethyl-2-diazomalonyl)-5-bromotryptophan is proposed and its relevance to the potency of the 5-BrTrp-based anti-sickling agents is discussed.

scholarly journals Plasma amino-acid determinations by reversed-phase HPLC: Improvement of the orthophthalaldehyde method and comparison with ion exchange chromatography

1992 ◽  
Vol 14 (4) ◽  
pp. 145-149 ◽  
Author(s):  
Frédéric Ziegler ◽  
Jacques Le Boucher ◽  
Colette Coudray-Lucas ◽  
Luc Cynober
Keyword(s):  
Amino Acid ◽  
Ion Exchange ◽  
Reversed Phase ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Reversed Phase Hplc ◽  
Suitable Alternative ◽  
Free Tryptophan ◽  
Rp Hplc ◽  
Low Concentrations

RP-HPLC with automated pre-column OPA derivatization is clearly a suitable alternative for assaying physiological AA and may be particularly useful for AA present at low concentrations (free tryptophan, plasma 3-methylhistidine).

Diet-related reference values for plasma amino acids in newborns measured by reversed-phase HPLC

1990 ◽  
Vol 36 (11) ◽  
pp. 1922-1927 ◽  
Author(s):  
P H Scott ◽  
S Sandham ◽  
S E Balmer ◽  
B A Wharton
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Reference Values ◽  
Detailed Examination ◽  
Reversed Phase ◽  
Reversed Phase Hplc ◽  
Highly Sensitive ◽  
Formula Group ◽  
Amino Acid Concentrations ◽  
Breast Fed

Abstract We have measured by reversed-phase HPLC concentrations of amino acids in plasma in groups of 80 normal appropriate-weight term babies fed from birth either a casein formula (WhiteCap SMA, n = 26), a whey formula (Gold Cap SMA, n = 26), or breast milk (n = 28). They were studied from day 11 to week 15 postpartum. The trend was towards an increase in amino acid concentrations in plasma with age, more marked in formula-fed than in breast-fed infants. Reference values were derived for each group. Both formula-fed groups showed several differences from the breast-fed group. Detailed examination indicated that tyrosine, phenylalanine, and methionine concentrations were increased in the casein-fed group greater than 20% of the time, but only threonine was similarly increased in the whey-fed group. Other amino acids, different ones for each formula group, were increased less frequently. There were no consistent correlations with any aspect of infant growth. Appropriate reference values are important for interpreting amino acid concentrations in plasma from newborns and for evaluating the effects of any future dietary modifications to infant formulas. HPLC analysis provides a suitable highly sensitive method for undertaking such studies.

Separation of Cobalt (III) Bis(ethylenediamine) Amino Acid Complexes by Reversed Phase HPLC

1981 ◽  
Vol 4 (4) ◽  
pp. 689-700 ◽  
Author(s):  
David A. Buckingham ◽  
Charles R. Clark ◽  
Roy F. Taskera ◽  
Milton T. W. Hearn
Keyword(s):  
Amino Acid ◽  
Reversed Phase ◽  
Reversed Phase Hplc ◽  
Amino Acid Complexes

Purification of a Novel Antibacterial Short Peptide in Earthworm Eisenia foetida

2004 ◽  
Vol 36 (4) ◽  
pp. 297-302 ◽  
Author(s):  
Yan-Qin Liu ◽  
Zhen-Jun Sun ◽  
Chong Wang ◽  
Shi-Jie Li ◽  
Yu-Zhi Liu
Keyword(s):  
Amino Acid ◽  
Molecular Mass ◽  
Reversed Phase ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Eisenia Foetida ◽  
Reversed Phase Hplc ◽  
Ammonium Sulfate Precipitation ◽  
Short Peptide ◽  
Tof Ms

Abstract A novel antimicrobial short peptide was purified from earthworm (Eisenia foetida) by a five-step protocol including ammonium sulfate precipitation, ultrafiltration, DE-52 ion exchange chromatography, Sephadex G-10 column chromatography, and C-18 reversed-phase HPLC techniques. The purified peptide was applied to the MALDI-TOP MS to determine the molecular mass and was also subjected to TOF MS-MS analysis to determine the amino acid sequence. As a result, a novel antibacterial peptide, named OEP3121, was obtained, with the molecular mass of 510.8 Da and the sequence being “ACSAG”.

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