Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

Calmodulin (CaM) is a ubiquitous Ca2+ binding protein that regulates a wide variety of cellular functions. Calmodulin was isolated from bovine testes with and without heat treatment to obtain heated and unheated samples, respectively. The same samples were used in subsequent enzymatic, chromatographic and electrophoretic studies. Enzymatic data utilizing phosphodiesterase indicate substantially lower activity in unheated CaM than in heated CaM. Chromatographic and electrophoretic data reveal that both heated and unheated CaM samples exist as a monomer (17 kD) and an aggregate (240 kD). The relative ratio of monomer to aggregate is dependent upon the pH of the medium. While the aggregate predominates at a pH above 6.5, the monomeric form predominates below pH 5.5. However, the pH-dependent aggregation is less pronounced in unheated CaM samples which also exhibit aggregates of other molecular weights. These results suggest the possible existence of a heat labile cellular component which affects the structural characteristics and possibly the function of calmodulin. Aggregation may also be involved in controlling calcium/calmodulin-modulated metabolism, in which calmodulin activity may be regulated by a disturbed equilibrium between monomer and aggregate as a function of subcellular local calcium concentration and pH.

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Poster Number PAyoung0620
Keywords: calmodulin, hplc, electrophoresis