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A major polypeptide (DE-1) was purified from King cobra venom by ion-exchange chromatography on CM-cellulose and also DEAE-cellulose and by gel filtration on Sephadex G-50. DE-1 comprises 60 amino acid residues and is cross-linked by four intrachain disulphide bridges. The complete primary structure of the polypeptide has been elucidated. The properties of DE-1 were compared with those of the short neurotoxin and the cytotoxin groups and of the angusticeps types. The sequence and some of the invariant residues of DE-1 resemble the short neurotoxin group and to some degree also the cytotoxin group, but it is a nontoxic (LD50 greater than 250 microgram/g of mouse) polypeptide.

Galactosyl hydroxylysine and deoxypyridinoline are at present the most promising markers of bone resorption. Various studies have indeed shown that these two markers discriminate with high accuracy subjects with different rates of bone turnover and that their accuracies and discriminate power are very similar. The aim of this paper is to compare the practicality and the reproducibility of the HPLC galactosyl hydroxylysine and deoxypyridinoline assays. In summary, this review shows that the galactosyl hydroxylysine and deoxypyridinoline HPLC assays differ mainly in the need, in using deoxypyridinoline, for an acid hydrolysis and a preextraction of the urine samples. This implies two major problems for deoxypyridinoline: 1) more time is required due to the cumbersome preanalytical procedures; and 2) a lower reproducibility. Our data, in fact, show that both the intra-assay and inter-assay coefficient of variation of the deoxypyridinoline assay are almost 100% higher than those of the galactosyl hydroxylysine assay.