Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
1981-12-15
pubmed:abstractText
The direct time-resolved fluorescence anisotropy of the single tryptophan residue in the polypeptide hormone adrenocorticotropin-(1-24) (ACTH) and the fluorescence decay kinetics of this residue (Trp-9) are reported. Two rotational correlation times are observed. One, occurring on the subnanosecond time scale, reflects the rotation of the indole ring, and the other, which extends into the nanosecond range, is dominated by the complex motions of the polypeptide chain. The fluorescence lifetimes of the single tryptophan in glucagon (Trp-25) and the 23-26 glucagon peptide were also measured. In all cases the fluorescence kinetics were satisfied by a double-exponential decay law. The fluorescence lifetimes of several tryptophan and indole derivatives and two tryptophan dipeptides were examined in order to interpret the kinetics. In close agreement with the findings of Szabo and Rayner [Szabo, A. G., & Rayner, D. M. (1980) J. Am. Chem. Soc. 102, 554-563], the tryptophan zwitterion exhibits emission wavelength dependent double-exponential decay kinetics. At 320 nm tau 1 = 3.2 ns and tau 2 = 0.8 ns, with alpha 1 = 0.7 and alpha 2 = 0.3. Above 380 nm only the 3.2-ns component is observed. By contrast the neutral derivative N-acetyltryptophanamide has a single exponential decay of 3.0 ns. The multiexponential decay kinetics of the polypeptides are discussed in terms of flexibility of the polypeptide chain and neighboring side-chain interactions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4361-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1981
pubmed:articleTitle
Time-resolved fluorescence and anisotropy decay of the tryptophan in adrenocorticotropin-(1-24).
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't