Glyoxalase I from Brassica juncea is a calmodulin stimulated protein.
Brassica juncea glyoxalase I (S-lactoylglutathione-lyase, EC 4.4.1. 5) is a 56 kDa, heterodimeric protein. It requires magnesium (Mg2+) for its optimal activity. In this report we provide biochemical evidence for modulation of glyoxalase I activity by calcium/calmodulin (Ca2+/CaM). In the presence of Ca2+ glyoxalase I showed a significant (2.6-fold) increase in its activity. It also showed a Ca2+ dependent mobility shift on denaturing gels. Its Ca2+ binding was confirmed by Chelex-100 assay and gel overlays using 45CaCl2. Glyoxalase I was activated by over 7-fold in the presence of Ca2+ (25 microM) and CaM (145 nM) and this stimulation was blocked by the CaM antibodies and a CaM inhibitor, trifluroperazine (150 microM). Glyoxalase I binds to a CaM-Sepharose column and was eluted by EGTA. The eluted protein fractions also showed stimulation by CaM. The stimulation of glyoxalase I activity by CaM was maximum in the presence of Mg2+ and Ca2+; however, magnesium alone also showed glyoxalase I activation by CaM.
Centre for Plant Molecular Biology, Jawaharlal Nehru University, New Delhi 110067, India. rdeswal@hotmail.com
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Sopory
D001937:Brassica / Q000201:enzymology*; D002118:Calcium / Q000378:metabolism; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D007791:Lactoylglutathione Lyase / Q000302:isolation & purification / Q000378:metabolism*; D008274:Magnesium / Q000378:metabolism; D014268:Trifluoperazine / Q000494:pharmacology
D002147:Calmodulin; D014268:Trifluoperazine; D007791:Lactoylglutathione Lyase; D008274:Magnesium; D002118:Calcium