Immunolocalization experiments indicate that both the subunit B of the NADP-linked chloroplastic glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13) and the NAD-linked cytosolic enzyme (EC 1.2.1.12) are present in the pea (Pisum sativum L.) leaf nucleus. Subunit A of the NADP-linked enzyme appears to be restricted to the chloroplast.