Copper-metallothioneins in the American lobster, Homarus americanus: potential role as Cu(I) donors to apohemocyanin
The physiological function of copper(I)-metallothionein is not well understood. The respiratory function of hemocyanin, a copper(I)-containing respiratory protein found in the hemolymph of many invertebrates, has been known a long time. However, the mechanism by which Cu(I) is inserted into the oxygen-binding site of apohemocyanin is completely unknown. This investigation tests that hypothesis that copper(I)-metallothionein may act as a Cu(I) donor to apohemocyanin. To this end, copper-binding proteins and hemocyanin were purified from the digestive gland and hemolymph of the American lobster, Homarus americanus. In the presence of ..beta..-mercaptoethanol, the copper-binding proteins can be resolved into three components of DEAE-cellulose. The first two have been characterized as metallothioneins. The cysteine content of the third component is half of that of components I and II. The purified proteins are not capable of transferring Cu(I) to the active sites of completely copper-free apohemocyanin. They are capable, however, of transferring Cu(I) to active sites of hemocyanin containing reduced amounts of Cu(I), suggesting that the conformational state of hemocyanin is the determining factor in the Cu(I) transfer mechanism.
- Research Organization:
- Duke Univ., Beaufort, NC
- OSTI ID:
- 5431316
- Journal Information:
- Environ. Health Perspect.; (United States), Journal Name: Environ. Health Perspect.; (United States) Vol. 65; ISSN EVHPA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
560304* -- Chemicals Metabolism & Toxicology-- Invertebrates-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
AQUATIC ORGANISMS
ARTHROPODS
BIOCHEMISTRY
CHEMICAL ACTIVATION
CHEMISTRY
COPPER COMPOUNDS
CRUSTACEANS
DECAPODS
HEMOCYANIN
INVERTEBRATES
LOBSTERS
METALLOPROTEINS
METALLOTHIONEIN
ORGANIC COMPOUNDS
PHYSIOLOGY
PROTEINS
TRANSITION ELEMENT COMPOUNDS