Diplocardia luciferin

Fig. 7.3.2 Comparison between the in vivo luminescence spectrum of a freshly exuded slime of Diplocardia longa and the in vitro luminescence spectrum measured with partially purified preparations of Diplocardia luciferin and luciferase. Reproduced from Bellisario et al., 1972, with permission from the American Chemical Society. Note that the in vitro emission maximum shifts to 490 nm when a sample of pure luciferin is used (Ohtsuka et al., 1976).

Fig. 7.3.3 Relationship between the concentration of H2O2 and the peak intensity of luminescence, when 0.2 ml of a H2O2 solution was injected into a mixture of 0.575 ml of 0.1 M potassium phosphate (pH 7.5), 0.025 ml of a solution of Diplocardia luciferin, and 0.2 ml of luciferase solution (0.12 mg). 1 LU = 109 quanta/s. From Bellisario et al., 1972, with permission from the American Chemical Society.

Fig. 7.3.4 Kinetic profiles of the Diplocardia bioluminescence reaction, when Diplocardia luciferase, H2O2, or Diplocardia luciferin was injected last. In each case, 0.1 ml of the last component was injected into 0.9 ml of the mixture of other components, to give the final concentrations Diplocardia luciferase, 0.1 unit/ml Diplocardia luciferin, 32 mM and H2O2, 32 mM, in 0.1 M potassium phosphate buffer, pH 7.5. From Rudie et al., 1981, with permission from the American Chemical Society.

Cypridina bioluminescence, 66, 69 firefly bioluminescence, 16 Diphyes, 334 Diplocardia, 335 Diplocardia longa, 216, 235, 240 Diplocardia luciferin, 235-238, 340, 342 See Earthworm luciferin Diplocladon, 337 Diplopoda (Millipedes), 307 Diplotrema, 235 Diptera, 1, 2, 25... 

Structure of luciferin (Ohtsuka et al., 1976). The luciferin of Diplocardia longa is a colorless liquid, and fairly stable at room temperature. It is soluble in polar organic solvents (methanol, ethanol, acetone, and methyl acetate) but insoluble in nonpolar solvents like hexane and carbon tetrachloride. Based on the chemical properties and spectroscopic data, the following chemical structure was assigned to the luciferin. 

The light yield and kinetics of in vitro luminescence vary with the order of the addition of components, as shown in Fig. 7.3.4 (Rudie et al., 1981). The light yield and initial rate are highest when luciferin and peroxide have been preincubated and the reaction is initiated by the injection of luciferase. Based on this and some other data, it was concluded that the true substrate of the Diplocardia luciferase is the H2O2 adduct of luciferin shown below (Rudie et al., 1981). 

Ohtsuka, H., Rudie, N. G., and Wampler, J. E. (1976). Structural identification and synthesis of luciferin from the bioluminescent earthworm, Diplocardia longa. Biochemistry 15 1001-1004. 

Quantula (Dyakia), 180, 334 Quantum yield, xvi, 361, 362 aequorin, 104, 106, 110 aldehydes in bacterial bioluminescence, 36, 41 Chaetopterus photoprotein, 224 coelenterazine, 85, 143, 149 Cypridina luciferin, 69-71 definition, xvi, 361 Diplocardia bioluminescence, 242 firefly luciferin, 12 fluorescent compound F, 73 Latia luciferin, 190 pholasin, 197 PMs, 286... 

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