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Biomedical subjects

M Burstein

Publications and source records attributed to M Burstein.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

Isolation of a beta 2-glycoprotein from human serum after precipitation with dextran sulfate and manganese chloride.

A new procedure was developed which affords isolation from among the euglobulins of human serum a beta 2-glycoprotein with a high degree of immunological and electrophoretic homogeneity. The isolated protein displays specific binding affinity for the activated form of the C4 component (C4b), and was identified by immunological and physico-chemical criteria as the C4 binding protein. The isolation procedure comprises the following steps: precipitation of euglobulins from serum at pH 5.5 and low ionic strength; precipitation of beta-lipoproteins from the redissolved precipitate with dextran sulfate and CaCl2; precipitation of a fraction of the lipoprotein-free euglobulins with dextran sulfate and MnCl2; redissolution of the precipitate and eventually chromatography on Sepharose 4B. The overall yield was between 15 and 20 per cent. The final product, devoid of immunologically detectable protein contaminants, was a homogeneous proline-rich monomeric beta 2-glycoprotein made up of eight disulfide-bonded polypeptide chains of the same molecular weight 63,000 +/- 3,000. Under non-reducing conditions, the molecular weight of both the native and the SDS-treated protein was 490,000 +/- 25,000. A monospecific antiserum to the isolated protein was raised in rabbits and used for the quantitation of the protein in sera of normal fasting donors; a mean concentration of 25 mg per 100 ml of serum (1 SD: 5) was established.

Chlorides↗
PubMedDate not supplied

[Specific rabbit abtiserum against human chylomicrons and very low density lipoproteins].

Rabbits were immunized by repeated intravenous injections of large amounts of chylomicrons plus VLDL isolated from human lipemic plasmas. The antisera were absorbed usccessively with lipoprotein free serum, HDL and LDL2. The absorbed antisera still precipitate chylomicrons and VLDL from sera of normal and hyperlipemic subjects (post-absorptive donors and fasting patients with type IV and type V hyperlipoproteinemia). By gel diffusion methods (immunoelectrophoresis and double diffusion in two dimensions), the antisera reveal a single precipitin line which stains better for lipid than for protein. This line is pronounced in VLDL-rich sera and absent in VLDL-free sera. The antisera react with chylomicrons plus VLDL delipidated by extraction with ethanol/diethyl ether; this shows that the antigenic site is an apoprotein; in contrast to apoprotein C, this apoprotein appears to be unique to the triglyceride-rich lipoproteins.

Animals↗