Glutathione S-transferase P1-1 (GSTP1-1) is a multifunctional enzyme which protects the cell from the influence of genotoxic factors and apoptosis. Contemporary knowledge about the GSTP1 molecule structure and the enzyme functions are summarized in this review. Also P1 isoform is compared to other glutathione S-transferases and structure-function relationships are emphasized. Novel functions of GSTP1 in cell signaling modulation, NO storage and metabolism are highlighted in this paper.