利用MALDI-TOF质谱结合磺基异硫氰酸苯酯(SPITC)化学辅助的从头测序(de novosequencing)方法,将用固相金属离子亲和色谱(immobilized metal affinity chromatography,IMAC)选择性地从混合物中亲和提取的磷酸肽进行磷酸化位点测定,该方...利用MALDI-TOF质谱结合磺基异硫氰酸苯酯(SPITC)化学辅助的从头测序(de novosequencing)方法,将用固相金属离子亲和色谱(immobilized metal affinity chromatography,IMAC)选择性地从混合物中亲和提取的磷酸肽进行磷酸化位点测定,该方法只有肽键断裂产生的带C端的碎片离子系列(y+离子系列)出现在质谱图中,图谱背景清晰,信噪比高,单纯的y+片段离子系列使得谱图解析变得非常容易,对于多磷酸化肽的磷酸化位点,不需借助于任何软件,只需简单地计算两峰之间的分子量之差即可确定.展开更多
The effects of toxic substance D1,extracted from burn eschars,on the hepatic mitochondrial respiratory function and its damages to the respirtatory chain were observed in the rat.It was found that the rate of stste 3r...The effects of toxic substance D1,extracted from burn eschars,on the hepatic mitochondrial respiratory function and its damages to the respirtatory chain were observed in the rat.It was found that the rate of stste 3respiration was inhibited and that of state 4 respiration stimulated by D1.There was an obvious dosage-effect relationship between D1 dosage and the rate of oxygen consumption, that is,the changes of the rate was slow in the range of low dosage and fast in the range of high dosage. The point of change was at 1 mg/ml of D1 concentration.The ratio of FCCP-stimulated respiration rate/state 4 respiration rate was decreased when D1 dosage was increased.The results of experiments were similar whether glutamate+malate or succinate were used as the substrate. The point of change was also at 1 mg/ml of D1 concentration. The decrease of FCCP-stimulated rate/state 4rate implied that the respiratory chain was damaged.But complex Ⅳ-the terminal segment of the chain-remained intact. Thus, the site of damage must be somewhere in complexesⅠ￣Ⅲ and/or complexes Ⅱ￣Ⅲ. Since NADH dehydrogenase and succinate dehydrogenase-the main enzymes in complexesⅠand Ⅱ-were not affected by D1 but NADH: cytochrome c reductase and succinate:cytochrome c reductase markedly inhibited, the site of damage was most likely located in complex Ⅲ-the bc1 complex.展开更多
Phosphorylation of protein is an important post-translational modification that enables activation of various enzymes and receptors included in signaling pathways. To reduce the cost of identifying phosphorylation sit...Phosphorylation of protein is an important post-translational modification that enables activation of various enzymes and receptors included in signaling pathways. To reduce the cost of identifying phosphorylation site by laborious experiments, computational prediction of it has been actively studied. In this study, by adopting a new set of features and applying feature selection by Random Forest with grid search before training by Support Vector Machine, our method achieved better or comparable performance of phosphorylation site prediction for two different data sets.展开更多
文摘利用MALDI-TOF质谱结合磺基异硫氰酸苯酯(SPITC)化学辅助的从头测序(de novosequencing)方法,将用固相金属离子亲和色谱(immobilized metal affinity chromatography,IMAC)选择性地从混合物中亲和提取的磷酸肽进行磷酸化位点测定,该方法只有肽键断裂产生的带C端的碎片离子系列(y+离子系列)出现在质谱图中,图谱背景清晰,信噪比高,单纯的y+片段离子系列使得谱图解析变得非常容易,对于多磷酸化肽的磷酸化位点,不需借助于任何软件,只需简单地计算两峰之间的分子量之差即可确定.
文摘The effects of toxic substance D1,extracted from burn eschars,on the hepatic mitochondrial respiratory function and its damages to the respirtatory chain were observed in the rat.It was found that the rate of stste 3respiration was inhibited and that of state 4 respiration stimulated by D1.There was an obvious dosage-effect relationship between D1 dosage and the rate of oxygen consumption, that is,the changes of the rate was slow in the range of low dosage and fast in the range of high dosage. The point of change was at 1 mg/ml of D1 concentration.The ratio of FCCP-stimulated respiration rate/state 4 respiration rate was decreased when D1 dosage was increased.The results of experiments were similar whether glutamate+malate or succinate were used as the substrate. The point of change was also at 1 mg/ml of D1 concentration. The decrease of FCCP-stimulated rate/state 4rate implied that the respiratory chain was damaged.But complex Ⅳ-the terminal segment of the chain-remained intact. Thus, the site of damage must be somewhere in complexesⅠ￣Ⅲ and/or complexes Ⅱ￣Ⅲ. Since NADH dehydrogenase and succinate dehydrogenase-the main enzymes in complexesⅠand Ⅱ-were not affected by D1 but NADH: cytochrome c reductase and succinate:cytochrome c reductase markedly inhibited, the site of damage was most likely located in complex Ⅲ-the bc1 complex.
文摘Phosphorylation of protein is an important post-translational modification that enables activation of various enzymes and receptors included in signaling pathways. To reduce the cost of identifying phosphorylation site by laborious experiments, computational prediction of it has been actively studied. In this study, by adopting a new set of features and applying feature selection by Random Forest with grid search before training by Support Vector Machine, our method achieved better or comparable performance of phosphorylation site prediction for two different data sets.
