Bacteroids from cobalt-deficient root nodules of Lupinus angustifolius L. cv. Unicrop were isolated and assayed for products of the cobalamin-dependent enzymes methionine synthetase, ribonucleotide reductase and methylmalonyl-CoA mutase.
Since bacteroids from lupin nodules did not show propionate-dependent O2 uptake, it was not possible to assess whether in vivo action of methylmalonyl-CoA mutase was affected, although it appears unlikely to be of major significance.
Cobalt deficiency decreased the DNA content per bacteroid in crown nodules, but not in later-formed lateral nodules. The percentage of amino-acid nitrogen accounted for by methionine was also lowered in bacteroids from crown nodules but not lateral nodules.