270 



LIGHT AND LIFE 



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TIME-MINUTES 

 lig. 5. Effect of ultraviolet liglit (3660 A) on a slant of Annillaria mellea. Cul- 

 ture was grown on 5% mycophil agar -(- 0.59!; yeast extract at pH 6.0 for 9 clays 

 at 18°C. Light source 4 inches from slant. 



wrapped with aluminum foil. The assays were conducted in the 

 following manner. When irradiated luciferase was used as the 

 enzyme, the dark control luciferin was used as the substrate; when 

 irradiated luciferin was the substrate, dark control enzyine was used 

 as the catalytic source. In one set of reactions both the irradiated 

 enzyme and substrate were used in the assay. Results of these assays 

 are presented in Table 1. 



With the reactants exposed for apjjroximately 80 minutes, the 

 values obtained for the (lO-minute dark control have been used as the 

 basis for comparative calculations. Where the reactants were exposed 

 to ultraviolet light for approximately 145 minutes, the 128-minute 

 dark control values have been used as a base for comparative calcu- 

 lations. The values given are the maximum light intensities attained 

 in terms of light iniits (LU) per milligram of enzyme protein (Imax) • 

 Also presented are the values for the increase in the initial rate of 



