D-erythrulose 1-phosphate <=> L-erythrulose 1-phosphate
d-erythrulose 1-phosphate <=> l-erythrulose 1-phosphate
D-erythrulose 1-phosphate <=> L-erythrulose 1-phosphate
d-erythrulose 1-phosphate <=> l-erythrulose 1-phosphate