摘要 : A 60 kDa heat stable calcium buffer protein, calreticulin, is co-purified with 17 kDa calmodulin from seedlings of Brassica juncea using anion exchange chromatography. The proteins were identified by MALDI-TOF/MS and LCMS, respect... 展开 A 60 kDa heat stable calcium buffer protein, calreticulin, is co-purified with 17 kDa calmodulin from seedlings of Brassica juncea using anion exchange chromatography. The proteins were identified by MALDI-TOF/MS and LCMS, respectively. Like other plant calreticulins, partially purified Brassica calreticulin had an affinity for Ca2+ as it stained blue with stains-all staining and is glycosylated as it stained pink with PAS staining. Further, the two were separated on Phenyl sepharose chromatography due to their differential affinity. BjCaM stimulated cAMP phosphodiesterase activity and showed Ca2+-dependent mobility shifts on one- and two-dimension SDS-PAGE. It stained blue with stains-all confirming it to be Ca2+ binding protein. BjCaM had cysteine residue as confirmed by Biotin Switch technique, but it did not nitrosylate. Co-purification of the two proteins indicates their possible interaction, which needs to be confirmed. 收起