The mRNA encoded by GrmM4 is highly induced in cotyledons two times during cotton (Gossypium hirsutum) embryo development and germination. It reaches a maximum concentration of about 1% of the total mRNA during the maturation stage, declines 6000-fold during the postabscission stage, and then again increases 1000-fold during the first 2 d of germination and seedling growth (Hughes and Galau, 1989). It is probably induced by different mechanisms during these two periods (Hughes and Galau, 1991). We report here that GrmM4 encodes a peroxidase (EC 1.11.1.7). Its mRNA is also present in roots and is induced 3-fold in young leaves of salt-stressed plants (D. Ritter, N. Trolinder, unpublished observations). The GrmM4 cDNA E39 from G. hirsutum L. cv Coker 201 (Hughes and Galau, 1989) was subcloned into pUC 19 and pBluescript and sequenced using externa1 and interna1 primers. It contains 1333 nucleotides and a poly(A) tail and encodes a peroxidase proprotein with a putative 23-amho acid signal sequence. The predicted mature protein is 35.1 kD, has an isoelectric point of 7.9, and contains the three peroxidase signature sequences at amino acid positions 49 to 64, 169 to 177, and 290 to 300, the eight Cys's involved in disulfide bridges, and the two His's involved with binding heme (Morgens et al., 1990).