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Abstract
SUMMARY: Antibody to pure Neurospora histidinol dehydrogenase has been prepared from rabbits. Extracts of Neurospora strains mutant at the his-3 locus have been examined by the double diffusion technique to ascertain whether or not they produce proteins which cross-react with this antibody. A total of 129 mutants, including 52 non-complementing ones, gave a positive reaction; no mutants have yet been observed which gave a negative result. In all cases two major precipitin bands were produced and it was shown that these corresponded to the 4S and the 7S forms of the enzyme. Dehydrogenation of histidinol by purified wild-type enzyme was completely inhibited by the antibody prepared against pure histidinol dehydrogenase and by antibody prepared against pure HD from the mutants k445 and k959, which produce a modified HD enzyme. HD activity was also inhibited by antibody prepared against partially purified homologous protein from the two noncomplementing mutants k492 and k474. It was possible to reduce the efficiency of neutralisation of HD by antibody if this was treated with extracts of mutants k492 and k474.
- Accepted:
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