PTP 1B Enzyme (human recombinant) (Prod. No. BML-SE332-9092)
(5 µg; 0.1 µg/µl in 50 mM HEPES, pH 7.2, 1 mM EDTA, 1 mM DTT, 0.05% NP-40, 10% (v/v) glycerol)
Storage: -70°C. Avoid freeze/thaw cycles

Substrate (“IR5” Insulin Receptor ß, residues 1142-1153, pY¹¹⁴⁶) (Prod. No. BML-P315-9090)
(1 mg; Lyophilized solid)
Storage: -20 or -70°C.

2X Assay Buffer (Prod. No. BML-KI467)
(20 ml; 100 mM MES, pH 6.0, 300 mM NaCl, 2 mM EDTA, 2 mM DTT, 0.1% NP-40 
Storage: -70°C

Biomol Red™ Concentrated Phosphate Detection Reagent (Prod. No. BML-KI468)
(5 ml; Liquid in screw-cap plastic bottle)
Storage: 4°C. Long-term at -70°C. 

Suramin (PTP1B inhibitor) (Prod. No. BML-KI469)
(10 mg; Solid)
Storage: -70°C

Phosphate Standard (Prod. No. BML-KI470)
(0.5 ml; 100 µM in 1X Assay Buffer)
Storage: -20 or -70°C

½-VOLUME MICROPLATE (Prod. No. BML-KI101)
Storage: RT

Store all components except the microtiter plate at -70°C for the highest stability. The PTP1B enzyme component BML-SE332-9092 must be handled particularly carefully in order to retain maximal enzymatic activity. Thaw it quickly in a RT water bath or by rubbing between fingers, then immediately store on an ice bath. The remaining unused enzyme should be ‘snap’ frozen, e.g. in liquid nitrogen or a dryice/ethanol bath, and stored at -70°C. If only a few assays are to be performed each day, the PTP1B may be divided into several aliquots (best if ≥10 µl)) to help minimize freeze/thaw cycles.