Purification And Identification Of HGH-like Protein In The Silkworm Pupae

Human Growth Hormone(hGH)is a peptide hormone secreted by the anterior pituitary gland in the brain. It enhances tissue growth by promoting protein synthesis, regulates metabolism and functioning of the immune system, plays important roles in many metabolic pathways. It is an important regulatory factor in the human body. The binding of hGH to its receptors on the cell membrane is essential for its functioning.We found a native protein in the silkworm pupae which can bind with the antibody of hGH protein, its molecular weight is about 30 kD, we named it the hGH-like protein and confirmed its presence in the silkworm pupae by Western Blotting and Immunoprecipitation. This research devoted in the purification and identification of hGH-like protein for further reasearch of its structure and biological functions.In this paper, lyophilized silkworm pupae powder were used as raw material, proteins of silkworm pupae was preliminarily isolated by homogenization, filtration, centrifugation, ammonium sulfate precipitation and ultrafiltration, concentrated by desalting and lyophilization, and then purified by Immunoprecipitation and Affinity Chromatography. After further isolation with 2-D electrophoresis, the interested protein dots on the gel were digested with trypsin, and the PMF (Peptide Mass Fingerprinting) were get from MALDI-TOF-MS. Then the PMF datas were analysed with PLGS Browser. It was finally confirmed that three native proteins in the silkworm pupae had been obtained, which were Bmb019519, Bmb021419 and Bmb027808, they are possibly the hGH-like protein or proteins which have interactions with hGH-like protein.Since the hGH protein is vital in human body and the silkworm is complete metamorphosis insects, further research of hGH–like protein may have important meanings and potential values in clinical applications.