Biomedical subjects

P Paysant

Publications and source records attributed to P Paysant.

At least 37 records · Page 2Linked to original sources

PubMed1976

[Heterogeneity of ovine prolactin after labeling with iodine 125: value of labeling with lactoperoxidase].

The authors have shown an heterogeneity of the ovine prolactine molecule after labelling with iodine 125. As well with chloramine T as with lactoperoxydase, it appears three molecular species which react with the immune serum antiprolactine (I.S.). The first species is of high molecular weight and is probably constituted of aggregates. Their combination with the I.S. is non specific and give blanks of high value. The second species is a dimere and the third one is the monomere. The two last species react with the I.S. and can give competition curves when they are choosen as tracer. However, if one uses as tracer a product obtained by labelling with chloramine T, the competition appears for high concentrations of native hormone. As if the I.S. recognizes much more the labelled protein than the native one. But if one uses the same species but labelled with lactoperoxydase, the competition appears for concentrations lower than five nanogrammes. In the same time one can see that the specificity toward different I.S. is modified. The authors think that the labelling with lactoperoxydase better preserves the tertiary structure of the native protein than do the labelling with chloramine T.

Animals↗

PubMed1976

[Iso-hormones : molecular forms of human chorionic somatomammotropin (HCS) (author's transl)].

The chorionic somatomammotropin hormone extracted from the human placenta exists in several molecular forms: Analytical electrophoresis on polyacrylamide gel permits separation of a highly anodic migration form : form 1 and another form migrating slightly faster than albumin : form 2. These two forms are active as measured by radioactive immunological analysis, form 2 being about 25 times more active than form 1. The two forms are mutually interconvertible. The two forms may also be separated by filtration on Sephadex G-50. However, they do not differ in molecular weight, they have the same coefficient of apparent diffusion, measured by analytic ultracentrifugation. Glutaraldehyde and 8 M urea do not modify their electrophoretic or chromatographic behaviour. On the other hand, the two forms differ in their tertiary structure, with the modification depending on the greater or lesser degree of oxidation of the intra-chain disulfide groups. The two forms also exist in placental culture media and the incorporation of tritiated leucine occurs preferably in form 1, The physiological significance of the two hormone pools is not clarified.

Chromatography, Gel↗

PubMed1975

Isohormones: molecular forms of the human chorionic somatomammotropic hormone.

The chorionic somatommaotropic hormone extracted from the human placenta exists in several molecular forms. Analytical electrophoresis in polyacrylamide gel permits separation of a highly anodic migration form, form 1, and another form migrating slightly faster than albumin, form 2. These two forms are active as measured by radioactive immunological analysis, form 2 being about 25 times more active than form 1. The two forms are mutually interconvertible. The two forms may also be separated by filtration on Sephadex G-50. However, they do not differ in molecular weight, they have the same coefficient of sedimentation and the same coefficient of apparent diffusion, measured by analytic ultracentrifugation. Glutaraldehyde and 8 M urea do not modify their electrophoretic or chromatographic behavior. On the hand, the two forms differ in their tertiary structure, with the modification depending on the greater or lesser degree of oxidation of the intra-chain disulfide groups. The two forms also exist in placental culture media and the incorporation of tritiated leucine occurs preferably in form 1. The physiological significance of the two hormone pools is not clarified.

Animals↗

PubMed1974