Coelenterazine h (2-Deoxycoelenterazine) drochloride, a coelenterazine derivative, is a luminescent substrate for RLuc8. Coelenterazine h drochloride is more sensitive to Ca2+, thus providing a valuable tool for measuring small changes in Ca2+ concentrations.
Coelenterazine h (1-10 μM) drochloride can be used as the luminescent substrate for RLuc8[4]. In the measurements of Ca2+ binding kinetics of BRAC, emission intensity of Venus (530 nm) from BRAC are monitored at 1 kHz just after rapid mixing of 5 nM BRAC protein with 20 μM coelenterazine-h drochloride in various concentration of Ca2+ buffer[4].
References:
[1]. Jiang T, et al. New bioluminescent coelenterazine derivatives with various C-6 substitutions. Org Biomol Chem. 2017 Aug 23;15(33):7008-7018.
[2]. M R Knight, et al. Imaging calcium dynamics in living plants using semi-synthetic recombinant aequorins. J Cell Biol. 1993 Apr;121(1):83-90.
[3]. Kazushi Suzuki, et al. Five colour variants of bright luminescent protein for real-time multicolour bioimaging. Nat Commun. 2016 Dec 14:7:13718.
[4]. enta Saito, et al. Auto-luminescent genetically-encoded ratiometric indicator for real-time Ca2+ imaging at the single cell level. PLoS One. 2010 Apr 1;5(4):e9935.