The nitrogen (N) metabolic experiments were made to estimate separately amino acid requirements of 4348 weeks old layers for maintenance, for protein accretion to estabolish models to estimate digestible amino acid re...The nitrogen (N) metabolic experiments were made to estimate separately amino acid requirements of 4348 weeks old layers for maintenance, for protein accretion to estabolish models to estimate digestible amino acid requirements. The regression relationship of nitrogen retention vs amino acid intake was estimated for each amino acid by giving, at rate of N intake of 091, 052, 015 and 0007gkg-1 body-weight (W075) per d, the semi-synthetic diets was made specially deficient in one amino acid. From the regression coefficients, it was calculated that, for the accretion of 1 g protein, the dietary digestible amino acid requirements were (mg) Thr 631, Val 1004, Met 399, Ile 886, Leu 1143, Phe 632, Lys 870, His 205, Arg 879, Trp 214, Met+Cys 776, and Phe+Tyr 1143. Daily amino acid requirements for N equilibrium were estimated to be (mgkg-1W075 per day) Thr 506, Val 747, Met 303, ILe 667 Leu 814, Phe 448, Lys 605 His 147, Arg 739 ,Trp 173, Met+Cys 586, and Phe+Tyr 839 The dietary degestible amino acid patterns for protein accretion and N equilibrium were also proposed. The models of estimating digestible amino acid requirements for the different productions were developed.展开更多
The mutation pattern in protein is a very important feature and is studied through various approaches including the study on mutation pattern in domains where amino acids are converted into numbers from letters. In th...The mutation pattern in protein is a very important feature and is studied through various approaches including the study on mutation pattern in domains where amino acids are converted into numbers from letters. In this study, we converted the amino acids in human adrenoleukodystrophy protein with its 128 missense mutations into random domain using the amino-acid pair predictability, and then we studied their mutation patterns. The results show 1) the mutations are more likely to target the amino-acid pairs whose actual frequency is larger than their predicted one, 2) the mutations are more likely to form the amino-acid pairs whose actual frequency is smaller than their predicted frequency, 3) mutations are more likely to occur at unpredictable amino-acid pairs, and 4) mutations have the trend to narrow the difference between predicted and actual frequencies of amino-acid pairs.展开更多
Lysostaphin is widely used in clinical settings against Staphylococcus aureus, but its mutants can abolish its killing activity. The difficulty in studies of mutations in lysostaphin is the shortage of data, which may...Lysostaphin is widely used in clinical settings against Staphylococcus aureus, but its mutants can abolish its killing activity. The difficulty in studies of mutations in lysostaphin is the shortage of data, which may need many decades to collect, although lysostaphin is so important for clinical therapeutics and drug development. In order not to passively wait for the accumulation of new data, in this study 1) the 23,442 mutations in 1408 proteins from databank were used to determine whether the mutations in lysostaphin follow the general mutation trend obtained from the databank, 2) the amino-acid pair predictability was used to explore the underlined mechanism for lysostaphin mutations, and 3) the amino-acid distribution probability was used to associate the mutation with dysfunction of lysostaphin. The results show that the mutations in lysostaphin follow the general trend of mutations in proteins;the underlined mechanism for mutations in lysostaphin is explainable from a viewpoint of randomness, and a mutation with increased distribution probability would have a larger chance to dysfunction lysostaphin. This study provides useful information for future design of anti-S. aureus drug and enzyme engineering.展开更多
目的建立柱前衍生高效液相色谱法(HPLC)测定紫贝齿饮片中11种氨基酸的方法,并比较不同基原的差异。方法以异硫氰酸苯酯为柱前衍生化试剂,采用C18色谱柱,流动相A为乙腈,流动相B为0.1 mol/L醋酸钠溶液(p H 6.5),梯度洗脱,检测波长254 nm,...目的建立柱前衍生高效液相色谱法(HPLC)测定紫贝齿饮片中11种氨基酸的方法,并比较不同基原的差异。方法以异硫氰酸苯酯为柱前衍生化试剂,采用C18色谱柱,流动相A为乙腈,流动相B为0.1 mol/L醋酸钠溶液(p H 6.5),梯度洗脱,检测波长254 nm,色谱柱温度40℃。运用主成分分析(PCA)、偏最小二乘法判别分析(PLS-DA)和方差分析研究了紫贝齿中4种基原的氨基酸成分的差异。结果11种氨基酸呈良好的线性关系(R>0.999);精密度、稳定性、重复性试验相对标准偏差(RSD)值分别小于1.77%、2.54%、1.98%;平均回收率为90.7%~108.9%(RSD为0.67%~1.58%,n=6)。紫贝齿4种基原之间氨基酸成分存在差异,并发现3种氨基酸差异性成分。结论建立的氨基酸测定方法稳定可靠,可用于紫贝齿饮片的质量评价。展开更多
目的建立冬枣中17种氨基酸含量的超高效液相色谱-串联三重四极杆质谱法(ultra performance liquid chromatography-triple quadrupole tandem mass spectrometry,UPLC-MS/MS)的测定方法及其指纹图谱,并结合多元统计分析,鉴别不同产地冬...目的建立冬枣中17种氨基酸含量的超高效液相色谱-串联三重四极杆质谱法(ultra performance liquid chromatography-triple quadrupole tandem mass spectrometry,UPLC-MS/MS)的测定方法及其指纹图谱,并结合多元统计分析,鉴别不同产地冬枣并进行整体质量评价。方法采用微波水解方式进行样品前处理,对8个不同产地的24批冬枣进行UPLC-MS/MS分析,以甲酸水溶液和甲酸的甲醇乙腈(1:4,V:V)溶液为流动相,进行梯度洗脱,电喷雾离子源正离子模式,多重反应监测(multiple reaction monitoring,MRM)模式采集;并结合聚类分析、主成分分析(principal component analysis,PCA)和正交偏最小二乘-判别分析(orthogonal partial least squares-discriminant analysis,OPLS-DA)对沾化冬枣及其他产地冬枣进行整体质量评价。结果UPLC-MS/MS氨基酸指纹图谱测定方法稳定性、重复性和精密度良好,相对标准偏差(relative standard deviation,RSD)分别为0.1%~2.8%、0.01%~1.87%和0.01%~0.78%。聚类分析与OPLS-DA均将样品聚为4类。OPLS-DA进一步筛选出7种对冬枣批次间差异起关键作用的氨基酸,PCA明确了影响冬枣品质的氨基酸组合。结论本研究建立的UPLC-MS/MS氨基酸指纹图谱测定方法可靠,结合聚类分析、OPLS-DA及PCA等化学模式识别技术,可有效区分沾化冬枣与不同产地冬枣,精准筛选标志性氨基酸及关键氨基酸组合,可为沾化冬枣的质量控制等方面提供依据。展开更多
A novel approach of sequence pattern correlation has been applied to predict an expected amino acid sequence from CID ESI MS spectra. The proposed approach deduces sequence patterns with no help from known protein da...A novel approach of sequence pattern correlation has been applied to predict an expected amino acid sequence from CID ESI MS spectra. The proposed approach deduces sequence patterns with no help from known protein database such that it is useful to identify an unknown peptide or new protein. The algorithm applies a cross correlation to match an experimental CID spectrum with predicted sequence pattern generated from fragmentation information. The fragmentation knowledge of both y series and other non y series are utilized to generate the predicted sequence patterns. In contrast to the normal de novo approach, the proposed approach is insensitive to mass tolerance and non susceptive to spectral integrality with no need for selection of a starting point.展开更多
文摘The nitrogen (N) metabolic experiments were made to estimate separately amino acid requirements of 4348 weeks old layers for maintenance, for protein accretion to estabolish models to estimate digestible amino acid requirements. The regression relationship of nitrogen retention vs amino acid intake was estimated for each amino acid by giving, at rate of N intake of 091, 052, 015 and 0007gkg-1 body-weight (W075) per d, the semi-synthetic diets was made specially deficient in one amino acid. From the regression coefficients, it was calculated that, for the accretion of 1 g protein, the dietary digestible amino acid requirements were (mg) Thr 631, Val 1004, Met 399, Ile 886, Leu 1143, Phe 632, Lys 870, His 205, Arg 879, Trp 214, Met+Cys 776, and Phe+Tyr 1143. Daily amino acid requirements for N equilibrium were estimated to be (mgkg-1W075 per day) Thr 506, Val 747, Met 303, ILe 667 Leu 814, Phe 448, Lys 605 His 147, Arg 739 ,Trp 173, Met+Cys 586, and Phe+Tyr 839 The dietary degestible amino acid patterns for protein accretion and N equilibrium were also proposed. The models of estimating digestible amino acid requirements for the different productions were developed.
文摘The mutation pattern in protein is a very important feature and is studied through various approaches including the study on mutation pattern in domains where amino acids are converted into numbers from letters. In this study, we converted the amino acids in human adrenoleukodystrophy protein with its 128 missense mutations into random domain using the amino-acid pair predictability, and then we studied their mutation patterns. The results show 1) the mutations are more likely to target the amino-acid pairs whose actual frequency is larger than their predicted one, 2) the mutations are more likely to form the amino-acid pairs whose actual frequency is smaller than their predicted frequency, 3) mutations are more likely to occur at unpredictable amino-acid pairs, and 4) mutations have the trend to narrow the difference between predicted and actual frequencies of amino-acid pairs.
文摘Lysostaphin is widely used in clinical settings against Staphylococcus aureus, but its mutants can abolish its killing activity. The difficulty in studies of mutations in lysostaphin is the shortage of data, which may need many decades to collect, although lysostaphin is so important for clinical therapeutics and drug development. In order not to passively wait for the accumulation of new data, in this study 1) the 23,442 mutations in 1408 proteins from databank were used to determine whether the mutations in lysostaphin follow the general mutation trend obtained from the databank, 2) the amino-acid pair predictability was used to explore the underlined mechanism for lysostaphin mutations, and 3) the amino-acid distribution probability was used to associate the mutation with dysfunction of lysostaphin. The results show that the mutations in lysostaphin follow the general trend of mutations in proteins;the underlined mechanism for mutations in lysostaphin is explainable from a viewpoint of randomness, and a mutation with increased distribution probability would have a larger chance to dysfunction lysostaphin. This study provides useful information for future design of anti-S. aureus drug and enzyme engineering.
文摘目的建立柱前衍生高效液相色谱法(HPLC)测定紫贝齿饮片中11种氨基酸的方法,并比较不同基原的差异。方法以异硫氰酸苯酯为柱前衍生化试剂,采用C18色谱柱,流动相A为乙腈,流动相B为0.1 mol/L醋酸钠溶液(p H 6.5),梯度洗脱,检测波长254 nm,色谱柱温度40℃。运用主成分分析(PCA)、偏最小二乘法判别分析(PLS-DA)和方差分析研究了紫贝齿中4种基原的氨基酸成分的差异。结果11种氨基酸呈良好的线性关系(R>0.999);精密度、稳定性、重复性试验相对标准偏差(RSD)值分别小于1.77%、2.54%、1.98%;平均回收率为90.7%~108.9%(RSD为0.67%~1.58%,n=6)。紫贝齿4种基原之间氨基酸成分存在差异,并发现3种氨基酸差异性成分。结论建立的氨基酸测定方法稳定可靠,可用于紫贝齿饮片的质量评价。
文摘目的建立冬枣中17种氨基酸含量的超高效液相色谱-串联三重四极杆质谱法(ultra performance liquid chromatography-triple quadrupole tandem mass spectrometry,UPLC-MS/MS)的测定方法及其指纹图谱,并结合多元统计分析,鉴别不同产地冬枣并进行整体质量评价。方法采用微波水解方式进行样品前处理,对8个不同产地的24批冬枣进行UPLC-MS/MS分析,以甲酸水溶液和甲酸的甲醇乙腈(1:4,V:V)溶液为流动相,进行梯度洗脱,电喷雾离子源正离子模式,多重反应监测(multiple reaction monitoring,MRM)模式采集;并结合聚类分析、主成分分析(principal component analysis,PCA)和正交偏最小二乘-判别分析(orthogonal partial least squares-discriminant analysis,OPLS-DA)对沾化冬枣及其他产地冬枣进行整体质量评价。结果UPLC-MS/MS氨基酸指纹图谱测定方法稳定性、重复性和精密度良好,相对标准偏差(relative standard deviation,RSD)分别为0.1%~2.8%、0.01%~1.87%和0.01%~0.78%。聚类分析与OPLS-DA均将样品聚为4类。OPLS-DA进一步筛选出7种对冬枣批次间差异起关键作用的氨基酸,PCA明确了影响冬枣品质的氨基酸组合。结论本研究建立的UPLC-MS/MS氨基酸指纹图谱测定方法可靠,结合聚类分析、OPLS-DA及PCA等化学模式识别技术,可有效区分沾化冬枣与不同产地冬枣,精准筛选标志性氨基酸及关键氨基酸组合,可为沾化冬枣的质量控制等方面提供依据。
文摘A novel approach of sequence pattern correlation has been applied to predict an expected amino acid sequence from CID ESI MS spectra. The proposed approach deduces sequence patterns with no help from known protein database such that it is useful to identify an unknown peptide or new protein. The algorithm applies a cross correlation to match an experimental CID spectrum with predicted sequence pattern generated from fragmentation information. The fragmentation knowledge of both y series and other non y series are utilized to generate the predicted sequence patterns. In contrast to the normal de novo approach, the proposed approach is insensitive to mass tolerance and non susceptive to spectral integrality with no need for selection of a starting point.
