CHEMILUMINESCENCE AND BIOLUMINESCENCE OF COELENTERAZINE ANALOGS POSSESSING AN ADAMANTYLMETHYL GROUP

Coelenterazine analogues possessing the adamantylmethyl group at the C 2 or C8 position were prepared to study their effects on chemi-and bio luminescence. Stability of the excited state coelenteramide analogues was significantly affected by the substitutions, resulting in a neutra l amide emission of chemiluminescence in diglyme-acetate buffer and in a blue-shifted emission of bioluminescence in Tris-HCl buffer. Substi tution of the adamantylmethyl group in the C8 position caused biolumin escence intensity to double. The 8-adamantylmethyl group may serve to orient the coelenterazine skeleton in a suitable position in the activ e site for efficient bioluminescence activity. Results with semi-synth etic AQs containing 8-adamantylmethyl analogues, and those of semi-syn thetic AQs containing 2-benzyl and 2-methyl analogues, indicate that a poAQ and apoAQ C145,152,180S have the ability to recognize the C2 and C8 side-chains in coelenterazine during AQ regeneration. (C) 1997 Else vier Science Ltd.