Participates in cysteine desulfurization mediated by NFS2 in chloroplast and NIFS1 in mitochondrion (PubMed:16437155). Activates the cysteine desulfurase activity of NFS2 (PubMed:16455656). Cysteine desulfurization mobilizes sulfur from L-cysteine to yield L-alanine and supplies the inorganic sulfur for iron-sulfur (Fe-S) cluster formation. Glutaredoxins regulate SUFE1 activity by inducing its reduction and deglutathionylation (PubMed:24203231). Cofactor biosynthesis; iron-sulfur cluster biosynthesis. Heterotetramer with NFS2 (PubMed:16455656). Interacts with NFS2 and NIFS1 (PubMed:16437155). Interacts in vitro with GRXS14, GRXS15, GRXS16 and GRXS17, but not with GRXC5 (PubMed:24203231). Interacts in vivo only with GRXS14 and GRXS16 (PubMed:24203231). Expressed in roots, leaves, stems and flowers. Glutathionylated. Glutathionylation strongly reduces the stimulation of NFS2 activity. Embryonic lethality when homozygous. Over-expression of SUFE1 leads to retarded growth and chlorosis. Belongs to the SufE family.