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Biomedical subjects

A Tardieu

Publications and source records attributed to A Tardieu.

At least 55 records · Page 3Linked to original sources
PubMed1980

Stopped-flow x-ray scattering: the dissociation of aspartate transcarbamylase.

A combination of stopped-flow and x-ray scattering techniques was used to study the dissociation of aspartate transcarbamylase (carbamoylphosphate:L-aspartate carbamoyltransferase, EC 2.1.3.2) with a 2:1 excess of p-chloromercuribenzenesulfonic acid (the ratio being calculated on a basis of reactive sites), in the presence and absence of the transition state analogue N-(phosphonacetyl)-L-aspartate. At 10 mg of protein per ml, the scattering curves allowed some details of the reaction to be followed with a time resolution down to 1 sec. The curves showed not only the dissociation of the enzyme complex but also the formation of the subunits. These results show that, with present facilities, x-ray scattering could be used to study dissociation or reassociation reactions with a time resolution of the order of 100 msec.

Allosteric Regulation↗
PubMed1979

Some comments on the article: 'The Structure of Human-Plasma Low-Density Lipoprotein B. An X-Ray Small-Angle Scattering Study' by K. Muller, P. Laggner, O. Glatter, and G. Kostner [Eur. J. Biochem. 82, 73--90 (1978)].

In their paper, K. Muller, P. Laggner, O. Glatter and G. Kostner report X-ray scattering and density experiments on human plasma low-density lipoprotein B, performed at different solvent densities (i.e. contrast variation method). The interpretation of the experimental data lead those authors to question the use of that method and particularly the use of the characteristic scattering functions in the study of serum lipoproteins. In the present paper it is shown that several aspects of their analysis are in fact highly questionable and that the objections raised are therefore unfounded.

Chemical Phenomena↗
PubMed1975

Neutron scattering study of human serum low density lipoprotein.

Regions of different proton density in the low density lipoprotein (LDL) particle from human serum have been determined by neutron scattering. From measurements in various H2O/D2O mixtures, the LDL particle appears to be quasi-spherical, with the centers of gravity of the hydrocarbon and polar regions coinciding. The average volume occupied by a particle was found to be 3.2 X 10-6 A-3, with the volume fraction occupied by the hydrocarbons being 60%. The ratius of gyration of the hydrocarbon region was 64 A, while that of the polar region was 100 A. consequently, the core of LDL is predominantly occupied by the hydrocarbon chains, while the outer shell is sparsely occupied by protein emerging from the lipid core.

Deuterium↗