Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.8 (phytase)
 1,997 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Modification of hemoglobin using inositol tetrakisphosphate (IP(4)) can improve the oxygen affinity of hemoglubin. Phytase was extracted from wheat bran and purified by ammonium sulphate fractionation, followed by Sephadex G-50 gel filtration and Mono Q chromatography. The purified phytase was used for hydrolysis of phytic acid under controled conditions. IP(4), as a major composition of the hydrolysate, was further purified on resin 714 column. The purified IP(4) was oxidized by periodate to obtain dialdehyde-IP(4). By the reaction between the aldehyde group of IP(4) derivative and the amino group of porcine hemoglobin (pHb), pHb-IP(4) conjugate was formed and was found to have better ability of O(2) binding and releasing than the native hemoglobin.
Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai) 2000
PMID:Preparation of Inositol Tetrakisphosphate and Its Application in Modification of Porcine Hemoglobin. 1211 Sep 9

It is difficult to obtain naturally occurring phytase having the required thermostability for application in animal feeding. The 1.3 kb thermal stable phytase gene (fphy) of Aspergillus fumigatus was synthesized by using a successive PCR method for the optimal expression in Pichia pastoris. Though the nucleotides of synthetic fphy share only 74% homology with the natural gene, the amino acid sequences coded by both genes were identical. After being cloned into the yeast expression vector (pPIC9) and inserted into the chromosome of Pichia pastoris by homologous recombination, phytase was expressed in the yeast and secreted from the cell. The strains for phytase over-expression were selected out by SDS-PAGE and enzyme analysis. After fermentation in 5 L fermention tank and induced by 0.5% methanol for 60 h, about 5.6 g purified phytase was obtained per liter culture fluid. The activity of phytase was 130 000 u per microlitre fluid. The thermostable phytase remained 40% active after exposure at 90 degrees for 80 min.
Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai) 2002 Nov
PMID:[High expression of a heat-stable phytase in Pichia pastoris]. 1241 14

Pichia pastoris has been developed to be a very efficient expression host for the heterogeneous proteins since its alcohol promoter was isolated and cloned, and its transformation technique was established. For further improving the secretion expression of heterogeneous proteins, in this research, the signal sequences were studied. At first, the Saccharomyces cerevisiae mating factor alpha prepro-leader sequence was synthesized using successive PCR and designated as MF4I. Then, ten different signal sequences were constructed by adding the N-terminal residues of Pichia pastoris Aox1 protein to the N-terminal of the MF4I. These ten signal sequences were used for directing phytase gene secretion in Pichia pastoris, the secretion of phytase were increased in Pichia pastoris strains containing new signal sequence. Among these strains, the phytase secretion was highest in strain contain signal sequence added with A, I, P three Aox1 N-terminal residues; the phytase secretion of Pichia pastoris was 90 mg/L in flake. The secretion was six-fold of that with original Saccharomyces cerevisiae mating factor alpha prepro-leader sequence. In addition, insert of ten residues E E A E A E A E P K can further increase the phytase secretion by 35%, the secretion reach 120 mg/L.
Sheng Wu Hua Xue Yu Sheng Wu Wu Li Xue Bao (Shanghai) 2003 Feb
PMID:[Influence of signal peptide sequences on the expression of heterogeneous proteins in Pichia pastoris]. 1254 23