Results 151 to 160 of about 20,144 (188)
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Leucine enkephalin—A mass spectrometry standard
Mass Spectrometry Reviews, 2011AbstractThe present article reviews the mass spectrometric fragmentation processes and fragmentation energetics of leucine enkephalin, a commonly used peptide, which has been studied in detail and has often been used as a standard or reference compound to test novel instrumentation, new methodologies, or to tune instruments.
Sztáray, Judit +3 more
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Rapid Communications in Mass Spectrometry, 2002
Abstract We have examined the multi‐stage collision induced dissociation (CID) of metal cationized leucine enkephalin, leucine enkephalin amide, and the N‐acetylated versions of the peptides using ion trap mass spectrometry. In accord with earlier studies, the most prominent species observed during the multi‐stage
Barr, J. M., Van Stipdonk, Michael J.
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Abstract We have examined the multi‐stage collision induced dissociation (CID) of metal cationized leucine enkephalin, leucine enkephalin amide, and the N‐acetylated versions of the peptides using ion trap mass spectrometry. In accord with earlier studies, the most prominent species observed during the multi‐stage
Barr, J. M., Van Stipdonk, Michael J.
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A heterocyclic analog of leucine‐enkephalin
Journal of Heterocyclic Chemistry, 1987AbstractA series of di‐, tri‐, tetra‐ and pentapeptide analogs of leucine‐enkephalin have been prepared in which the initial tyrosinylglycine fragment has been replaced by the 5,6‐dihydro‐5,5‐dimethyl‐2‐oxo‐3‐phenyl‐1(2H)‐pyrazineacetic acid moiety.
Albert A. Carr +4 more
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The Journal of Clinical Endocrinology & Metabolism, 1983
Plasma methionine-enkephalin-like and leucine-enkephalin-like immunoreactivity (met-enkephalin-LI and leu-enkephalin-LI, respectively) in six normal subjects and six patients with pheochromocytoma were determined. The contents of met-enkephalin-LI and leu-enkephalin-LI in two of six pheochromocytomas were 40- to 50-fold higher and those in the other ...
T, Yoshimasa +6 more
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Plasma methionine-enkephalin-like and leucine-enkephalin-like immunoreactivity (met-enkephalin-LI and leu-enkephalin-LI, respectively) in six normal subjects and six patients with pheochromocytoma were determined. The contents of met-enkephalin-LI and leu-enkephalin-LI in two of six pheochromocytomas were 40- to 50-fold higher and those in the other ...
T, Yoshimasa +6 more
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Hydrolysis of Peripheral Leucine Enkephalin in Allergic Asthma
Clinical Immunology, 1999Plasma hydrolysis of leucine enkephalin was studied in a group of patients affected by seasonal allergic asthma in acute and quiescent stage; data were compared with those obtained from a control group of healthy volunteers. Results obtained indicate a statistically significant reduction of leu-enkephalin hydrolysis in allergic subjects.
L, Fuso +6 more
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Clinical and Experimental Pharmacology and Physiology, 1989
SUMMARY1. A radio‐immunoassay (RIA) for methionine‐enkephalin sulfoxide was developed and was used to measure methionine‐enkephalin, after oxidation, in the rat brain.2. The RIA was performed together with assays that use commercially available met‐and leu‐enkephalin antisera.3.
G K, Tiong, J E, Olley
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SUMMARY1. A radio‐immunoassay (RIA) for methionine‐enkephalin sulfoxide was developed and was used to measure methionine‐enkephalin, after oxidation, in the rat brain.2. The RIA was performed together with assays that use commercially available met‐and leu‐enkephalin antisera.3.
G K, Tiong, J E, Olley
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SYNTHESIS OF CHROMOPHORIC DEHYDRO ANALOG OF LEUCINE ENKEPHALIN
International Journal of Peptide and Protein Research, 1981Dehydropeptides incorporating a highly colored group have been prepared by reacting peptide esters with 4‐(4′‐dimethyl‐amino‐3′‐nitro) benzylidene‐2‐phenyloxazolin‐5‐one. This method allows a rapid synthesis of colored analogs of physiologically important peptides, in this case, leucine enkephalin.
D J, Phelps, J R, Godin
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Distribution of leucine-enkephalin in bone and joint tissues
Neuropeptides, 2002The distribution and concentration of leu-enkephalin in periosteum, cortical bone, bone marrow and synovial membrane of normal rats were analysed. Periosteum, cortical bone and bone marrow of the rat femurs were collected as well as the ankles. The distribution of leu-enkephalin was analysed by immunoelectron microscopy and the concentration of leu ...
Wu, Qinyang +3 more
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A conformational analysis of leucine enkephalin as a function of pH
Biopolymers, 2002AbstractThe conformations of Leu enkephalin in aqueous solution have been investigated as a function of pH using molecular dynamics simulations. The simulations suggest the peptide backbone exists as a mixture of folded and unfolded forms (approximately 50% each) at neutral pH, but is always unfolded at low or high pH.
Mahalaxmi, Aburi, Paul E, Smith
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Glycation of Leucine-Enkephalin: Imidazolidinones and Amadori Compounds
2001In an effort to elucidate the properties and reactivity of the parent free sugars, herein we present the formation of leucine-enkephalin related imidazolidinones, as well as Amadori compounds from glucose, mannose or galactose and leucine-enkephalin. We will present the influence of solvent , temperature and added base on the rate of formation of these
Horvat, Štefica, Roščić, Maja
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