Luminescence of Cypridina Luciferin in the Presence of Human Plasma Alpha 1-Acid Glycoprotein

Abstract

The enzyme Cypridina luciferase (CLase) enables Cypridina luciferin to emit light efficiently through an oxidation reaction. The catalytic mechanism on the substrate of CLase has been studied, but the details remain to be clarified. Here, we examined the luminescence of Cypridina luciferin in the presence of several proteins with drug-binding ability. Luminescence measurements showed that the mixture of human plasma alpha 1-acid glycoprotein (hAGP) and Cypridina luciferin produced light. The total value of the luminescence intensity over 60 s was over 12.6-fold higher than those in the presence of ovalbumin, human serum albumin, or bovine serum albumin. In the presence of heat-treated hAGP, the luminescence intensity of Cypridina luciferin was lower than in the presence of intact hAGP. Chlorpromazine, which binds to hAGP, showed an inhibitory effect on the luminescence of Cypridina luciferin, both in the presence of hAGP and a recombinant CLase. Furthermore, BlastP analysis showed that hAGP had partial amino acid sequence similarity to known CLases in the region including amino acid residues involved in the drug-binding ability of hAGP. These findings indicate enzymological similarity between hAGP and CLase and provide insights into both the enzymological understanding of CLase and development of a luminescence detection method for hAGP.

Chemiluminescence of coelenterazine catalyzed by cyclodextrins as a luminescence reference standard for luminometers v2

“…Several relevant findings were reported for vargulin -a substrate of Vargula/Cypridina luciferase -which has the same imidazopyrazinone core as CTZ. Its chemiluminescence was also shown to be enhanced by albumin and a few other binding proteins (Kanie et al, 2020). β-CD and its methylated derivatives increased the already relatively high chemiluminescence of MCLA (a vargulin analog), with 10 mM dimethyl-β-CD providing a 6-fold increase in luminescence (Mitani et al, 1995).…”

Pseudo-Luciferase Activity of the SARS-CoV-2 Spike Protein for Cypridina Luciferin

“…1 Although a luciferin typically emits light only in the presence of the corresponding luciferase, IPT luciferin often exhibits nonspecific luminescence reactions toward nonluciferase proteins or other biomolecules, as observed in both cellularand animal-imaging studies. 3 To date, some reports have revealed that nonluminescent proteins, such as serum proteins including human plasma alpha 1-acid glycoprotein, 4 bovine serum albumin, 3 and insulin, 5 can catalyze the nonspecific luminescence oxidative reaction of natural IPT luciferin, even though they have not been assigned an EC number and are not recognized as enzymes. We have recently demonstrated that CTZ derivative HuLumino1, which is an IPT luciferin with a side-chain chemical structure that is different from that of CTZ, is selectively recognized and enzymatically oxidized to exhibit light by one of several hydrophobic pockets (drug-binding site 2) in human serum albumin (HSA).…”

“…12,13 Moreover, some studies have suggested that the luminescence reaction of IPT luciferin requires a hydrophobic pocket as an oxidative reaction field. 4,6,14 Therefore, we hypothesized that specific luminescence detection of the S protein could be achieved by selecting a luciferin that specifically fits into the hydrophobic pockets of the S protein.…”

Comparative Investigation of the Chemiluminescent Properties of a Dibrominated Coelenterazine Analog

“…One of the most studied CL/BL substrates is Coelenterazine (Clz, Scheme 1 ) [ 1 , 3 , 16 , 17 , 18 , 19 , 20 , 21 ], which is present in many marine BL organisms [ 22 ]. Clz is capable of both BL (with luciferase enzymes or photoproteins) [ 3 ] and CL (triggered without an enzyme/protein by oxygenation) [ 23 , 24 , 25 ]. These Clz-based reactions follow a mechanism that consists in two steps: first, there is the oxygenation of the imidazopyrazinone core that leads to the formation of dioxetanone, the high-energy peroxide intermediate; the dioxetanone will undergo thermolysis almost instantly due to its high instability, during which the reacting molecules can cross directly to singlet excited states, resulting in the chemiexcited light emitter coelenteramide [ 1 , 3 , 4 , 20 ].…”

“…Another example of natural CL/BL imidazopyrazinone compounds found in marine species is Cypridina luciferin (CypLuc, Scheme 1 ), which can be found in the ostracod Cypridina hilgendorfii [ 23 , 24 ]. Besides natural imidazopyrazinones, synthetic analogs have also been developed over the years, with some being already commercialized.…”