Properties of Cypridina Luciferin

Chemical structure. The structure of the free base of Cypridina luciferin (C22H27ON7, Mr 405.50) was determined by Kishi et al. (1966a,b) as shown below (A) its sec-butyl group is in the same configuration as in L-isoleucine. The structure of oxyluciferin reported by the same authors contained an error, and the structure was corrected later as shown in Fig. 3.1.8 (McCapra and Chang, 1967 Stone, 1968). 

oxyluciferin has a molecular formula of C21H27ON72HCI. The total synthesis of Cypridina luciferin has been accomplished (Kishi et al., 1966c Inoue et al., 1969 Karpetsky and White, 1971 Nakamura et al., 2000). 

Properties. Cypridina luciferin is soluble in water, methanol and other alcoholic solvents, but not in most aprotic solvents. The ultraviolet absorption spectra of luciferin and oxyluciferin are shown in Fig. 3.1.3. Luciferin in neutral solutions is yellow (lmax 432 nm  

Chemiluminescence. Cypridina luciferin emits light in various organic solvents in the presence or absence of a base. The most efficient 

It should be noted that Cypridina luciferin emits a fairly strong chemiluminescence in aqueous solutions in the presence of various lipids and surfactants, even in the complete absence of luciferase. The luminescence is especially conspicuous with cationic surfactants (such as hexadecyltrimethylammonium bromide) and certain emulsion materials (such as egg yolk and mayonnaise). Certain metal ions (especially Fe2+) and peroxides can also cause luminescence of the luciferin. Therefore, great care must be taken in the detection of Cypridina luciferase in biological samples with Cypridina luciferin. 

---