INTERNATIONAL JOURNAL OF AGRICULTURE & BIOLOGY ISSN Print: 1560–8530; ISSN Online: 1814–9596 19–0761/2020/23–2–279–287 DOI: 10.17957/IJAB/15.1286 http://www.fspublishers.org Full Length Article To cite this paper: Sabullah MK, MR Sulaiman, MY Shukor, JA Gansau, F Ahmad, A Khalid, SA Ahmad (2020). Identification of some novel biomarkers for assessment of copper sulphate toxicity in liver of Puntius javanicus through proteomic analyses. Intl J Agric Biol 23:279‒287 Identification of Some Novel Biomarkers for Assessment of Copper Sulphate Toxicity in Liver of Puntius javanicus through Proteomic Analyses Mohd Khalizan Sabullah 1,2 , Mohd Rosni Sulaiman 3 , Mohd Yunus Shukor 1 , Jualang Azlan Gansau 2 , Fisal Ahmad 3 , Ariff Khalid 4 and Siti Aqlima Ahmad 1* 1 Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia 2 Faculty of Science and Natural Resources, Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah, Malaysia 3 Faculty of Food Science and Nutrition, Universiti Malaysia Sabah, 88400 Kota Kinabalu, Sabah, Malaysia 4 Biomedical Science Programme, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia * For correspondence: aqlima@upm.edu.my Received 06 May 2019; Accepted 02 August 2019; Published 16 January 2020 Abstract Copper is extensively released into the environment, affecting the natural habitat of surrounding organisms especially the aquatic life. The aim of this study is to explore the different protein expressions on different concentrations of CuSO 4 . Puntius javanicus liver was used as a tool to investigate the biomarkers and mechanisms of copper toxicity to P. javanicus through proteomic assessment after being exposed with different concentrations of CuSO 4 (0, 0.1, 0.3, 0.5, 1.0 and 5.0 mg/L). P. javanicus liver was extracted (TCA-acetone extraction) and electrophoresed (IEF and 2D PAGE). Ten protein spots were found to be significantly different in their expression and subsequently identified via matrix assisted laser desorption/ionization tandem time-of-flight (MALDITOF). Three protein spots were further identified as new alternative biomarkers for copper toxicity namely, zinc finger C4H2 domain-containing protein, insulin gene enhancer protein isl-2a and synaptic vesicle membrane protein VAT-1 homolog-like. The present study could provide an additional understanding on the hepatotoxic mechanisms of copper as well as enhance the development of biomarkers for an efficient monitoring of the contamination level in the environment based on proteomic assessment. © 2020 Friends Science Publishers Keywords: Proteomic; Copper; Liver; Biomarker; Puntius javanicus; Proteins Introduction Copper (Cu) is an element that has many well-known functions. For instance, Cu either in the form of metal ions (Cu 2+ ) or salts (CuSO 4 and CuCl 2 ) are considered as vital components in the production of pesticides and fertilizers. The solid form of Cu is also an important component in electrical and electronic devices ( Oliveira-Filho et al. 2004; Salama 2005; Shomar 2006; Yang et al. 2011; Obrador et al. 2013). The agricultural application of pesticides and fertilizers had enhanced farm productivity and reduced losses in plantations, resulting in the increase of crop production and quality. However, misapplication and poor management associated with their excessive use may lead to environmental contamination, especially in water bodies as the final target, thus affecting organisms in aquatic ecosystem such as planktons, fish and aquatic plants (Ahmad et al. 2016; Basirun et al. 2019a). Cu is an essential heavy metal together with iron, zinc and magnesium, which play a major role as a biological regulator in fish, especially for neurotransmitter function, respiration, reactive oxygen species (ROS) scavenger and as cofactors for numerous enzymes (Lauer et al. 2012; Singh et al. 2012; Zubair et al. 2013). Unfortunately, Cu may become toxic at higher concentrations if it exceeds the internal needs. The toxicity of copper has been described to alter fish behavior from the biomolecular to the cellular level. Simpson et al. (2006) discussed the induction of oxidative stress by Cu, which causes damage on cell membranes and other biochemical compounds. This activity has been proven by Varanka et al. (2001) and Sabullah et al. (2014a) in their studies where the acute effects of copper sulphate (CuSO 4 ) toxicity caused parenchymal abnormalities and nucleus fragmentation in the liver of fish. Cu toxicity also affects both in vivo and in vitro activity of antioxidants and detoxifying enzymes in fish liver such as superoxide dismutase, catalase, glutathione S-transferase, glutathione peroxidase, metallothionine and