Wheat germ (Triticum aestivum) calmodulin (CaM) sequence is unique in that it contains cysteine at residue position 26 (Cys26). In contrast to mammalian CaMs, which lack cysteine, this preparation is ideal for applications requiring both calmodulin activation and residue specific tagging. The single SH moiety at Cys26 can be labeled using a variety of sulfhydryl (SH) reactive protein-modification reagents such as fluorescent maleimide derivatives. Additionally, since wheat germ CaM contains only a single tyrosine residue (Tyr138) verses two tyrosine residues found in mammalian CaM, Tyr138 serves as a mono-specific C-terminal region labeling site. Using Cys26 and Tyr138 allows wheat germ CaM to be independently derivatized at both N- and C-terminal regions within the molecule for structural, proteomic biomarker discovery and protein-protein interaction studies. Wheat germ CaM also has no tryptophan resulting in a distinctive absorbance spectrum when compared to mammalian CaM sequences.