Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Abstract A cobalt-resistant strain of Neurospora crassa (cor) is 20-fold more resistant to Co when compared with the wild type. DEAE-cellulose and metal-chelate affinity chromatography of cell-free extracts separated cobalt into protein-bound and free ionic fractions. In N. crassa cor about 80% cobalt of cell-free extracts was protein bound while the same in wild type was only 25%. Cobalt content of the protein-bound fraction increased with time and cobalt concentration in the growth medium, and was not influenced by related metal ions. A cobaltoprotein (CBP) which is overproduced in N. crassa cor and constitutes up to 12% of total protein of extracts was purified. CPB is a brown coloured (absorption peaks at 275, 350 and 440nm), small molecular weight glycoprotein (Mr 8200 daltons) with 28 - 30% carbohydrate (mannose). CBP has 70 μg cobalt mg-1 protein. Cysteine, glycine, glutamic acid and aspartic acid are the major amino acid constituents. The role of CBP in cobalt resistance is discussed in relation to other known metalloproteins involved in resistance. © Rapid Science 1998.
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