Intensity of each protein was quantified by calculation of spot v

Intensity of each protein was quantified by calculation of spot volume after WZB117 normalization of the image using the total spot volume normalization method multiplied by the total area of all the spots. The calculation of the theoretical molecular weight and pI values of the identified protein spots is based on algorithms included in the ImageMaster 2D Elite 4.01 analysis software package. Statistical analysis was carried out with SPSS for Windows 10.0 and Excel. MALDI-TOF-MS Differential protein spots were Selleckchem SHP099 excised from preparative gels using biopsy

punches and transferred to a 1.5 ml siliconized Eppendorf tube. Proteins in-gel was digested as previously described [6]. The gel-spots were destained in the destaining solution consisted of 100 mmol/L Na2S2O3 and 30 mmol/L K3Fe(CN)6 (1:1). The proteins-contained gel-spots were reduced in the reduction buffer consisted of 100 mmol/L NH4HCO3, 10 mmol/L DTT for

1 h at 57°C, and alkylated in the alkylation buffer consisted of 100 mmol/L NH4HCO3and 55 mmol/L iodocetamide in the dark for 30 min at room temperature. The gel pieces were dried in a vacuum centrifuge. The dried gel-pieces were incubated in the digestion solution learn more consisted of 40 mmol/L NH4HCO3, 9%ACN and 20 μg/mL PD184352 (CI-1040) trypsin(Sigma, St. Louis, USA) for 16 h at 37°C. The tryptic peptide mixture was extracted and purified with Millipore ZIPTIP™C18 column. The purified tryptic peptide mixture was mixed with α-cyano-4-hydroxycinnamic acid (CCA) matrix solution, and vortexed lightly. A volume (1 μl) of the mixture containing CCA matrix was loaded on a stainless steel plate, and dried in the air. The samples were analyzed with Applied Biosystems Voyager System 4307 MALDI-TOF Mass Spectrometer (ABI). The parameters were set up

as following: positive ion-reflector mode, accelerating voltage 20 kV, grid voltage 64.5%, mirror voltage ratio 1.12, N2 laser wavelength 337 nm, pulse width 3 ns, the number of laser shots 50, acquisition mass range 1000–3000 Da, and delay 100 nsec, and vacuum degree 4×10-7Torr. A trypsin-fragment peak was served as internal standard for mass calibration. A list of the corrected mass peaks was the peptide mass fingerprinting (PMF). Database analysis Proteins were identified with peptide mass fingerprinting data by searching software PeptIdent http://​www.​expasy.​org/​ and Mascot http://​www.​matrixscience.​com. Mascot Distiller was used to detect peaks by attempting to fit an ideal isotopic distribution to the experimental data. The searching parameters were set up as following[6, 7]: the mass tolerance was ± 0.

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