Thr101 is an inhibitor (IC50=2.9 µM) of phosphomannose isomerase (PMI).PMI can compete with phosphomannose mutase 2 (PMM2) for the binding site of Man-6-P and convert mannose-6-phosphate (Man-6-P) into fructose-6-phosphate (Fru-6-P) .Thr101 only specifically inhibits PMI and not PMM2. Thr101 can be used for research of congenital disorder of glycosylation type Ia (CDG-Ia)[1].