ABSTRACT
Human kallikrein-1 (hK1) gene was cloned from kidney tissues cDNA, it was inserted into the plasmid pPICZalphaA, then the yeast expression vector pPICZalpha-hK1 was constructed. After transformed into Pichia pastoris host X33, high-level expression transformants were screened by escalating the concentration of Zeocin (from 500 to 700 microg/mL) of YPD plate and medium. When temperature was 30 degrees C, pH 6.0 with induction duration of 64 hours in the 30 L fermenter, the highest yield can reach about 6500 u/L (1.25 g/L). The variation of glycosylation resulted in two kinds of molecules, i.e. rhK1-H with a heavy molecular weight and rhK1-L with a light one. rhK1 was purified from the supernatant through Phenyl hydrophobic interaction, Cu(2+)-charged Chelating and Anion-exchange chromatography. 0.28 g rhK1-H and 0.62 g rhK1-L can be purified from one liter supernatant. The yield recovery was 72% with a purity of > 96%. So far our yield of rhK1 is superior than known recombinant expression method reported by other researchers.
Subject(s)
Humans , Amino Acid Sequence , Base Sequence , Chromatography, Ion Exchange , Methods , Genetic Vectors , Genetics , Kidney , Metabolism , Molecular Sequence Data , Pichia , Genetics , Metabolism , Recombinant Proteins , Genetics , Tissue Kallikreins , GeneticsABSTRACT
Wavelet transforms are used in detecting ECG characteristic points recognition.The relationships between ECG characteristic points and the modulus maximum pairs of their wavelet transfoms are expounded.The application perspective of wavelet transforms to ECG characteristic points recognition is predicted through the analysis of the results.
ABSTRACT
This paper introduces the hardware of data acquisition system based on LabVIEW platform, i.e. the system for data acquisition and control. The system is composed of the units for signal selection, programmable magnification, filtration, restriction, and A/D and D/A conversion circuits. With the system, the following can be available including eight-channel low-frequency signals, eight options on programmable magnification, 1000Hz low-pass filter, 50Hz power-frequency trap, and A/D and D/A conversion.