[Improvement of carbohydrate deficient transferrin measurement by capillary zone electrophoresis using immunosubtraction of immunoglobulins and transferrin].

CDT (Carbohydrate Deficient Transferrin) is considered as the most efficient biomarker of alcohol abuse available for routine use. Among the various methods developed for its measurement, capillary zone electrophoresis (CZE) on the multicapillary analyzer Capillarys2 provides high quality results at high throughput. However, the non CDT specific measurement of protein absorbance at 200 nm may bring abnormal profiles in samples from patients with high polyclonal immunoglobulin level or monoclonal component.

Sidedness of ceramide-phosphoethanolamine synthesis on rat liver plasma membrane.

Phosphatidylethanolamine:ceramide-ethanolaminephosphotransferase catalyzes the synthesis of ceramide-ethanolamine, a sphingomyelin analogue. Its transverse localization in rat liver plasma membrane was studied by treating intact and deoxycholate- or Triton X-100-disrupted membrane vesicles with trypsin or bacterial protease. The latency of ATPase was preserved during protease treatment; its value was 80% in the membrane vesicles obtained by sucrose gradient procedure alone and 91.

Sidedness of ceramide-phosphoethanolamine synthesis on rat liver and brain microsomal membranes.

Phosphatidylethanolamine:ceramide-ethanolamine-phosphotransferase catalyzes the synthesis of ceramide-phosphoethanolamine, a sphingomyelin analogue. Its localization was studied in rat liver and brain microsomes. After testing the integrity and the sidedness of microsomal vesicles, trypsin treatment of intact or deoxycholate-disrupted microsomes made it possible to conclude that both the transferase and the ceramide-phosphoethanolamine are located in the cisternal leaflet of the membrane bilayer.

Sphingomyelin and ceramide-phosphoethanolamine synthesis by microsomes and plasma membranes from rat liver and brain.

Pulse-chase experiments showed that phosphatidylethanolamine (PE) was the direct precursor for ceramide-phosphoethanolamine, a sphingomyelin analogue, in the same way as phosphatidylcholine was for sphingomyelin. Ceramide-phosphoethanolamine could be identified by incorporation of radioactivity from labeled PE, as well as by its stability in alkaline methanolysis and its ability to be methylated by S-adenosyl-methionine. Ceramide-phosphoethanolamine synthesis from labeled exogenous PE seemed to be independent of exogenous ceramide; it was proportional to the amount of incubated membrane, when taking into account the isotopic dilution of labeled precursor by endogenous PE.

[Biosynthesis and metabolism of phosphonolipids and phospholipids in rat hepatocytes and Saccharomyces cerevisiae].

In rat hepatocytes, ciliatine (2 aminoéthylphosphonic acid) is incorporated into phosphonolipid (PnE) by the same pathway leading from phosphorylethanolamine to phospholipid (PE). The two resulting lipids are isolated from mitochondria and microsomes. The rates of biosynthesis are quite comparable; the processes of trimethylation and of in vitro transfer in the presence of a specific exchange protein are very similar.