Objective: To investigate the structure

function and pathological action of leptin. The human leptin was expressed in pichia pastoris yeast. Methods: The cDNA encoding human leptin was amplified by reverse transcription-polymerase chain reaction (RT-PCR) using directly total RNA as template which was isolated from human abdomen fatty cells. The recognition sequence GAATTC of restriction enzyme EcoRI was joined to the 5’Ⅰ′end of primer 1 and recognition sequence CGGCCG of restriction enzyme Notto the 5end of Primer 2. The αPCR product (cDNA fragment) was inserted into expression vector (pPICZ)

expressed in pichia pastoris yeast GS115. Results: The PCR product is 462bp

In SDS-PAGE

expressed protein was showed as one specific band

whose molecular weight is 17kD. The protein has been purified by using affinity chromatography with the polyhistidine tag binding to Ni 2+. Conclusion: The cDNA of human leptin has been successfully expressed in pichia pastoris yeast.