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Biomedical subjects

T J Swift

Publications and source records attributed to T J Swift.

17 recordsLinked to original sources
PubMed1980

N6-Trimethyl-lysine metabolism. Structural identification of the metabolite 3-hydroxy-N6-trimethyl-lysine.

(1)H and (13)C nuclear-magnetic-resonance spectroscopy and functional-group analysis were used to determine the molecular structure of an isolated metabolite (II(b)) of trimethyl-lysine as 3-hydroxy-N(6)-trimethyl-lysine, an important intermediate in the conversion of trimethyl-lysine into trimethylammoniobutyrate and carnitine [Hoppel, Cox & Novak (1980) Biochem. J.188, 509-519]. Functional-group analysis revealed the presence of a primary amine and reaction of metabolite (II(b)) with periodate yielded 4-N-trimethylammoniobutyrate as a product, showing 2,3-substitution on the molecule and suggesting that the 3-substitution on the molecule may be an alcohol ([unk]CH-OH), amine ([unk]CH[unk]-NH(2)) or carbonyl ([unk]C=O) functional group. (1)H integration ratios, (1)H and (13)C chemical-shift data and (1)H and (13)C signal multiplicities from the sample (II(b)) were used to complete the identification of metabolite (II(b)) as 3-hydroxy-N(6)-trimethyl-lysine. For example, the proton multiplet at delta 4.2p.p.m. and doublet at delta 4.1p.p.m., positions representative of amine or alcohol substitution on methylene carbon atoms, integration ratios of 1:1:2:9:4 and a positive ninhydrin test suggest 3-hydroxy-N(6)-trimethyl-lysine as the molecular structure for metabolite (II(b)). (13)C chemical-shift data obtained from the sample (II(b)) and compared with several model compounds (trimethylammoniohexanoate, trimethyl-lysine and 3-hydroxylysine) resulted in generation of the spectrum of the metabolite and allowed independent identification of metabolite (II(b)) as 3-hydroxy-N(6)-trimethyl-lysine. The (1)H spectrum of erythro- and threo-3-hydroxylysine are presented for comparison, and the (1)H and (13)C n.m.r. spectra of the erythro-isomer support this analysis.

Carbon Radioisotopes↗
PubMed1972

Barbiturate interaction with phosphatidylcholine.

A hydrogen-bonding interaction between phenobarbital or pentobarbital with phosphatidylcholine in chloroform is indicated by the effects of added phosphatidylcholine on the infrared and proton magnetic resonance spectra of these barbiturates. The nitrogenbound proton of the barbiturate and the orthophosphate moiety of the phosphatidylcholine molecule appear to be involved. The more pronounced effect with the two barbiturates occurs in the proton magnetic resonance spectra of phenobarbital with increased amounts of phosphatidylcholine. A plot of the chemical shift of phenobarbital N-H against the concentration of phosphatidylcholine is linear and gives an extrapolated shift of 260 Hz (2.6 ppm) at 35 degrees C for a phosphatidylcholine-phenobarbital ratio of unity, pure 1:1 complex. It is suggested that the general depressant nature of barbiturates may be accounted for by their association in a similar fashion with a number of other phosphate-containing molecules.

Chemical Phenomena↗
PubMed1970

Direct evidence from nuclear magnetic resonance studies for bound sodium in forg skeletal muscle.

The recent work of Cope on (23)Na magnetic resonance studies of frog muscle has been repeated with the view of investigating certain objections which can be raised concerning the original studies. The present work leads to the conclusion that Cope's results concerning bound sodium are essentially correct in that a large fraction of the (23)Na present does not contribute normally to a detectable nuclear magnetic resonance (NMR) signal. This "missing" signal can be detected at high radio-frequency intensity however, and a signal-saturation study distinctly reveals its presence.

Animals↗
PubMed1969

A proton spin-echo study of the state of water in frog nerves.

A proton spin-echo study of the water in the sciatic nerve trunk of the bullfrog reveals two distinct types of water as distinguished by their spin-spin relaxation times. The relative concentrations of these two types were determined for nerves which had been treated with normal Ringer's solution and also for nerves which had been treated with potassium-doped (0.15 M) Ringer's solution. In both cases the relative concentrations are the same as those previously determined through signal integration of high resolution proton magnetic resonance spectra obtained for the same systems, although the high resolution studies were performed on nerves doped with paramagnetic ions and the spin-echo studies were performed on undoped nerves. The doping procedure would appear to be a valid and very useful way of studying water in this neural system.

Animals↗