Depletion method of blood plasma ascorbate
US6989143B1 · kind B1 · utility
Assignees
Inventors
Key dates
| Filing date | May 2, 2000 |
| Grant date | Jan 24, 2006 |
| Priority date | — |
| Expiry date | May 2, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC12Y110/03003
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
Artificial modulation of ascorbate level was investigated in mice capable of de novo synthesis of ascorbate. When mice were given exogenous ascorbate or its physiological precursor, L-gulono-γ-lactone, the plasma level of ascorbate was elevated substantially but immediately returned to the basal levels. Comparably, the administration of ascorbate oxidase caused a rapid disappearance of plasma ascorbate but followed by an immediate restoration of ascorbate. These results indicate the difficulties encountered in the modulation of ascorbate level in the animal. However, the circulation life of the exogenous ascorbate oxidase in the animal was successfully extended by chemical modification with methoxypolyethylene glycol. The modified enzyme retained a full activity and exerted a remarkably prolonged depletion of plasma ascorbate compared with the native enzyme. This study suggests that the chemically modified ascorbate oxidase should find many uses in the animal studies on ascorbate since it was found to deplete plasma ascorbate even in the ascorbate-synthesizing animal in the absence of dietary control. The enzyme should prove to be useful in tumor control because there are tumor sys…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.