核酸、核苷酸及蛋白质质量与摩尔数的转换
1. 核苷酸分子量1个脱氧核糖核酸碱基的平均分子量为333 Daltons1个核糖核酸碱基的平均分子量为340 Daltons2. DNA碱基对分子量一个DNA碱基对（钠盐）的平均分子量 = 650 道尔顿双链DNA分子的分子量(道尔顿) = 碱基对数目×6503. 光吸收值与浓度1 OD260 dsDNA =50 μg/ml = 0.15 mmol/L1 OD260 ssDNA =33 μg/ml = 0.10 mmol/L1 OD260 ssRNA =40 μg/ml = 0.12 mmol/L4. 浓度与光吸收值1 mmol/L dsDNA= 6.7 OD2601 mmol/L ssDNA= 10.0 OD2601 mmol/L ssRNA= 8.3 OD2605. 质量与摩尔数对于dsDNA分子每对碱基的平均分子量(MW)是660 pg/pmolμg×(106pg/1μg)×(pmol/660pg)×(1/N)=pmol N 是核酸碱基对数1 μg 1,000bpDNA = 1.52 pmol1 μg pUC18/19DNA (2,688bp) = 0.57 pmol1 μg pBR322 DNA(4,361bp) = 0.36 pmol1 μg SV40 DNA(5,243bp) = 0.29 pmol1 μg FX174 DNA(5,386bp) = 0.28 pmol1 μg M13mp18/19DNA (7.250bp) = 0.21 pmol1 μg l phageDNA (48,502bp) = 0.03 pmol对于ssDNA分子每个碱基的平均分子量(MW)是330 pg/pmolμg×(106pg/1μg)×(pmol/330pg)×(1/N)=pmol6. 摩尔数与质量对于dsDNA分子每对碱基的平均分子量(MW)是660 pg/pmolpmol×N×(660pg/pmol)×(1μg/106pg)=μg1 pmol 1,000bpDNA = 0.66 μg1 pmol pUC18/19DNA (2,688bp) = 1.77 μg1 pmol pBR322DNA (4,361bp) = 2.88 μg1 pmol SV40 DNA(5,243bp) = 3.46 μg1 pmol FX174DNA (5,386bp) = 3.54 μg1 pmol M13mp18/19 DNA (7.250bp) = 4.78 μg1 pmol l phageDNA (48,502bp) = 32.01 μg对于ssDNA分子每个碱基的平均分子量(MW)是330 pg/pmolpmol×N×(330pg/pmol×(1μg/106pg)=μg7. 浓度C (mmol/L orpmol/ml) = OD260/(0.01*NC (ng/ml) =OD260*MW/(0.01*N)MW — molecularweight；N —number ofbases；OD260 —absorbance at 260 nm8. 质量浓度与摩尔浓度1ng/μl Nbp DNA
9. 核酸末端浓度双链DNA分子的末端摩尔数 = 2 ×DNA质量（克）/ DNA分子量（道尔顿）限制性内切酶酶切后的DNA末端摩尔数:环状DNA分子：2×DNA摩尔数×位点数pmol ends = pmol DNA *number of cuts * 2线性DNA分子：2×DNA摩尔数×位点数+2 ×DNA摩尔数pmol ends = pmol DNA * (number of cuts *2 + 2)1 μg 1,000bp DNA = 3.04 pmol ends1 μg pUC18/19 DNA (2,688bp) = 1.14 pmol ends1 μg pBR322 DNA (4,361bp) = 0.7 pmol ends1 μg SV40 DNA (5,243bp) = 0.58 pmol ends1 μg FX174 DNA (5,386bp) = 0.56 pmol ends1 μg M13mp18/19 DNA (7.250bp) = 0.42 pmol ends1 μg l phage DNA (48,502bp) = 0.06 pmol ends10. 双链DNA与寡核苷酸的熔短于25bp的双链寡核苷酸：Tm = 2 (A + T) + 4 (G + C)长于25bp的双链寡核苷酸：Tm=81.5+16.6(lg[J+])+0.41(%GC)–(600/N)–0.63(%Formamide)N —— 引物的长度(以碱基数计算)J+ —— 单价阳离子浓度11. DNA与表达蛋白之间分子量换算9 amino acid≈ 1k Da Protein1 kb DNA = 333 amino acid ≈ 37k DaProtein10,000 Da Protein ≈ 270 bp DNA30,000 Da Protein ≈ 810 bp DNA50,000 Da Protein ≈ 2701 bp DNA100,000 Da Protein ≈ 27 kb DNA12. 蛋白质质量与摩尔数的转换100pmol的100kDa蛋白分子=10μg100pmol的50kDa蛋白分子=5μg100pmol的10kDa蛋白分子=1μg100pmol的1kDa蛋白分子=100ng13. DNA电泳基本参数琼脂糖和聚丙烯酰胺凝胶中DNA迁移率线性DNA分离建议凝胶浓度分离范围(bp)琼脂糖浓度分离范围(bp)PAGE浓度1,000~30,0000.5%100~1,0003.5%800~12,0000.7%80~5005.0%500~10,0001.0%60~4008.0%400~7,0001.2%40~20012.0%200~4,0001.5%5~10020.0%50~2,0002.0%变性、非变性PAGE胶中染料迁移率PAGE浓度相当核苷酸片段大小，bp溴酚蓝二甲苯青3.5%1004605.0%652608.0%4516012.0%207015.0%156020.0%1245