Abstract
Calmodulins (CaM) were isolated and characterized from two well-known latex producing plants, Papaver somniferum and Euphorbia lathyris. The molecular weights of both were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 17,000 comparable to that of bovine brain CaM. Amino acid compositions also compared similarly with those of known CaMs, with regard to the presence of trimethyllysine and the ratio of phenylalanine to tyrosine. The Cornish-Bowden equation (SDeltan) revealed strong statistical correlations of P. somniferum and E. lathyris CaM with those of other plants and animals, although their amino acid compositions were not identical. Both plant CaM stimulated CaM dependent cAMP phosphodiesterase: for Papaver somniferum the K(a) was found to be 1.09 nanomolar and for Euphorbia lathyris, 2.01 nanomolar.