You could get protocol from my following attached papers except for glutathione peroxidase. For glutathione peroxidase you look for literature. If hope glutathione peroxidase activity could be detected using reduced glutathione and H2O2 as a substrates following the protocol used for other peroxidases. You can detect consumption of reduced glutathione using DTNB. Papers are attached herewith.
You can refer these articles and it may helpful for your work
1. Shalavadi MH, Chandrashekhar VM, Avinash SP, Sowmya C, Ramkishan A. Neuroprotective activity of Stereospermum suaveolens DC. against 6-OHDA induced Parkinson’s disease model. Indian Journal of Pharmacology 2012;44:737-43.
2. M.H. Shalavadi, V.M. Chandrashekhar, A. Ramkishan, R.B. Nidavani, B.S. Biradar. Neuroprotective activity of Stereospermum suaveolens against global cerebral ischemia rat model. Phamaceutical Biology 2013;51(8):955–960.