Oxygen-binding characteristics of erythrocyte in children with type I diabetes mellitus of different duration.

Oxygen-binding properties of erythrocyte hemoglobin were studied in children with type 1 diabetes mellitus by Raman spectroscopy. The content of hemoglobin-oxygen complexes increased significantly only in children with lasting disease (more than 1 year); oxygen-binding capacity of hemoglobin is significantly changed, while its capacity to release oxygen remained unchanged. These changes were paralleled by alteration of hemoglobin affinity for oxygen. The area and content of hemoglobin were studied by laser interference microscopy. Hemoglobin content increased significantly in erythrocytes of patients with a more than 1-year history of type 1 diabetes mellitus. In these children, a significant inverse correlation between oxyhemoglobin fraction, oxygen binding capacity, and cholesterol content was found, this clinical parameter positively correlated with affinity for oxygen measured by Raman spectroscopy.

Characteristics of binding of zwitterionic liposomes to water-soluble proteins.

The interactions of zwitterionic phospholipids phosphatidylcholine and phosphatidylethanolamine with protein proteinase inhibitors aprotinin and Bowman-Birk soybean proteinase inhibitor have been investigated. An increase in the hydrophobicity of the liposome surface was shown to be an important factor for the formation of proteoliposomes. According to (31)P-NMR spectra, incorporation of the proteins into the liposomes does not influence the structural organization of the surface of the liposomes. Increasing the ionic strength does not inhibit the process of proteoliposome formation. Fluorescence assay of the complexes of anthracene-labeled phospholipids with the rhodamine B-labeled protein showed that after the encapsulation into the liposomes, the protein is located inside the particles and between the bilayers. Also, the effect of phospholipids with saturated fatty acid residues on the protein-lipid interaction was studied by differential scanning calorimetry. The results indicate that water-soluble proteins efficiently interact with zwitterionic phospholipids, and the encapsulation of the proteins into the liposomes is provided by electrostatic and hydrophobic forces (in the case of aprotinin) or predominantly by hydrophobic forces (Bowman-Birk soybean proteinase inhibitor).

Evaluation of phospholipid composition of erythrocytes from healthy volunteers by the method of high-performance liquid chromatography with a light scattering detector.

Phospholipid composition of lipid extract from erythrocytes of healthy volunteers was evaluated by means of high-performance liquid chromatography with light scattering detection. The lower and upper limits of the major (phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin) and minor phospholipids (phosphatidylserine) were estimated in 61 extracts. No significant differences were found between men and women.

Interaction of native Bowman-Birk soybean protease inhibitor and its hydrophobized derivative with multilamellar vesicles of soybean phospholipids.

The interaction of native Bowman-Birk soybean protease inhibitor (BBI) and its hydrophobized derivative with multilamellar vesicles of various soybean phospholipids was investigated. Decrease in pH and introduction of negatively charged components to the lipid mixture increased BBI content in the protein-lipid complex. This suggests a contribution of electrostatic forces in the protein-lipid interaction. Protein hydrophobization insignificantly influenced BBI binding to lipids. In the complex with lipids, both proteins (BBI and its hydrophobized derivative) retained high anti-chymotrypsin activity (75-100%), which was not influenced by the presence of the ionic detergent sodium deoxycholate.

Interaction of trypsin with multilamellar vesicles of soybean lipids.

The pH dependence of complex formation of trypsin with multilamellar vesicles (MLV) of soybean lipids has been investigated. The lipids were characterized by the same phospholipid composition, but the content of other lipids differed. Decrease of pH or introduction of negatively charged components into the lipid samples increased trypsin content in the protein-lipid complexes. This suggests electrostatic interaction between the protein and soybean lipids. The dependence of trypsin activity in the complexes with MLV on their concentration and on the presence of an ionic detergent was studied. Trypsin-MLV interaction did not result in complete inactivation of the protein molecules. Moreover, the effects of dilution and addition of ionic detergent on trypsin activity were additive. Using a fluorescence technique, complex formation with MLV was found to stabilize trypsin molecules, preventing their autolysis.