Possesses cystine lyase activity in vitro. Does not possess tyrosine aminotransferase, alanine aminotransferase, aspartate aminotransferase and tryptophan aminotransferase activities. H2O + L-cystine = NH4(+) + pyruvate + S-sulfanyl-L-cysteine Homodimer. Expressed in cotyledons, sepals, pistils, flower buds, phloem companion cells and vascular tissues of petiole, leaf, filament and fruit. Induced by jasmonate (PubMed:11500565, PubMed:9342878). Induced by coronatine (PubMed:11500565, PubMed:16008101). Induced by 12-oxo-phytodienoic acid (OPDA) (PubMed:11500565). Induced by wounding (PubMed:11500565, PubMed:9342878, PubMed:18247047). Induced by abscisic acid (ABA) (PubMed:9342878). Induced by the cell wall elicitin from the non-pathogenic biocontrol agent Pythium oligandrum (PubMed:19304739). Induction by wounding requires COI1. Belongs to the class-I pyridoxal-phosphate-dependent aminotransferase family. CORI3 was initially isolated by Lopukhina et al (PMID:11500565) as tyrosine aminotransferase (TAT). The authors also measured a TAT activity in vitro, even though relatively weak. Jones et al (PMID:12525491) showed that CORI3 possesses cystine lyase (CL) activity, but lacks TAT activity in vitro. In addition, CL activity is not inhibited by saturation of L-tyrosine in the medium. As CORI3 should bind L-tyrosine to catalyze TAT activity, this excludes a TAT activity for CORI3. Jones et al. made the statment that TAT activity resulted probably from residual native TAT-catalyzing proteins present in the purified preparations employed by Loupokhina et al.