7th Asia-Pacific Conference on Plasma Physics, 12-17 Nov, 2023 at Port Messe Nagoya

Catalase enzyme inhibition's effect on plasma medicine

Pankaj Attri1*, Takamasa Okumura1, Kazunori Koga1,2, and Masaharu Shiratani1
Kyushu University1, National Institutes of Natural Sciences2e-mail (speaker): attri.pankaj.486@m.kyushu-u.ac.jp.
Biochemical studies of tissue reveal that the endogenouslevels of antioxidant enzymes vary greatly across tissue
types [1]; this reflects differences in development andmetabolism across different organ systems [2]. In mostcancer cells, the intrinsic levels of antioxidant enzymes
are low compared to healthy cells or non-transformed
cells [3]. This suggests that most cancer cells lack thebiochemical machinery to metabolize H2O2 effectively.
Plasma medicine is a new field that uses cold
atmospheric plasma (CAP) for various medical
applications, such as sterilization, wound healing, blood
coagulation, and cancer treatment [3]. CAP interacts withthe oxygen, nitrogen, water, etc., in air to produce various
radical and non-radical species, for example, hydroxyl
radicals (•OH), superoxide (O2•−), singlet oxygen (1O2),nitrogen dioxide (NO2), hypochlorite (ClO−), atomicoxygen (O), and nitric oxide (NO). During the plasma–liquid interactions, some relatively long-lifetime reactive
species are generated in liquid, such as hydrogen peroxide(H2O2), nitrites (NO2−), and nitrates (NO3−) [4]. To
understand the CAP mechanism in the complex bioorganism it is important to understand CAP action on theproteins.
To understand the plasma treatment effect on
the structure and activity of catalase, we treated bovine
liver catalase using pulsed DBD and Jet for 5, 10, and 20
min. We investigated the structural and thermodynamicchanges in catalase through UV-visible, fluorescence, andcircular dichroism spectroscopies after DBD and Jet
plasma treatments at various time intervals. We have also
performed mass spectrometry analysis to reveal thepossible modified amino acids in catalase after both typesof plasma treatments (DBD and jet). The jet plasma
treatment modifies the catalase structure to a greater
extent than the DBD plasma. Additionally, we performed
molecular dynamics simulations based on the massspectrometry analysis to gain insight into the structuraldeformation of catalase. Finally, we have observed that
inhibition of catalase enzyme in A375 cancer cells
increases the plasma treatment (DBD and jet) efficiency.
Molecular dynamic simulation studies show more change
in RMSD for catalase after Jet treatment than DBD
treatment, as shown in Figure 1. Therefore, we conclude
that the enzymatic activity of catalase in cancer cells
decreases after plasma treatment. Still, this decrease is notstrong enough to completely inhibit the catalase cellularfunction (to metabolize H2O2) in cancer cells.

Figure 1: RMSD and Rg values of Catalase before andafter plasma modification
Acknowledgment
This work is supported by JSPS-KAKENHI grant number
22H01212. Additionally, partly supported by JSPS
KAKENHI Grant Number JP16H03895, JP19H05462,
JP22K03586, JP20H01893, JP20K14454, JSPS Core-toCore Program "Data Driven Plasma Science", Plasma BioConsortium, Adaptable and Seamless Technology transfer
Program through Target-driven R&D (A-STEP) fromJapan Science and Technology Agency (JST) Grant
Number JPMJTR20RU, and Center for Low-temperaturePlasma Sciences, Nagoya University.
References[1] S. L. Marklund, et al., Cancer Res. 42, 1955–1961(1982).
[2] T. D. Oberley and L.W. Oberley, Histol. Histopathol.
12, 525–535 (1997).
[3] P. Attri, Anti-Cancer Agent Me, 18, 768 (2018),[4] P. Attri, F. Tochikubo, J. H. Park, E. H. Choi, K.
Koga, M. Shiratani, Sci. Rep. 8, 2926 (2018).