Secreted production of an elastin-like polypeptide by Pichia pastoris

Elastin-like polypeptides (ELPs) are biocompatible designer polypeptides with inverse temperature transition behavior in solution. They have a wide variety of possible applications and a potential medical importance. Currently, production of ELPs is done at lab scale in Escherichia coli shake flask cultures. With a view to future large scale production, we demonstrate secreted production of ELPs in methanol-induced fed-batch cultures of Pichia pastoris and purification directly from the culture medium. The production of ELPs by P. pastoris proved to be pH dependent within the experimental pH range of pH 3 to 7, as an increasing yield was found in cultures grown at higher pH. Because ELP produced at pH 7 was partly degraded, a pH optimum for production of ELP was found at pH 6 with a yield of 255 mg of purified intact ELP per liter of cell-free medium

Oxidants and antioxidants of erythrocytes

Erythrocytes contain reactive forms of oxygen (superoxide anion, hydrogen peroxide, hydroxyl radical) and reactive form of nitrogen (nitric oxide anion, S-nitrosothiols, peroxynitrite anion). Reactive oxygen species and reactive nitrogen species inactivate enzymatic (methemoglobin reductase, Cu, Zn-Superoxide dismutase, catalase, glutathione peroxidase) and non-enzymatic (glutathione, alpha-tocopherol, beta-carotene, ascorbate) antioxidants. Their quantity in erythrocytes increases in case of exposure to xenobiotics, in erythrocytes containing pathological hemoglobin, in erythrocytes with the enzymatic defects of the glycolytic or pentose cycle, in erythrocytes found in arterial and venous thrombi, and in the blood extravasated to tissues and body cavity. In such cases are observed in erythrocytes: structure modification of hemoglobin and membrane proteins, and lipids peroxidation. These processes cause changes of shape, decrease of flexibility, decrease of resistance to hemolysis, Heinz's bodies production and shorten the life span of red cells

Cathepsin D inhibitors

Inhibitors of cathepsin D belong to chemical compounds that estrify carboxyl groups of the Asp33 and Asp231residues of its catalytic site, penta-peptides containing statin, i.e. the amino acid similar in structure to the tetraedric indirectproduct, and polypeptides found in the spare organs of many plants and forming permanent noncovalent complexes withcathepsin. Cathepsin D activity is also inhibited by alpha2-macroglobulin and antibodies directed against this enzyme.Methods used to determine the activity and concentration of these inhibitors and their analytical, preparative and therapeuticapplications are discussed