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 Daltons 1个核糖核酸碱基的平均分子量为340 Daltons 2. 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×650 3. 光吸收值与浓度 1 OD260 dsDNA =50 μg/ml = 0.15 mmol/L 1 OD260 ssDNA =33 μg/ml = 0.10 mmol/L 1 OD260 ssRNA =40 μg/ml = 0.12 mmol/L 4. 浓度与光吸收值 1 mmol/L dsDNA= 6.7 OD260 1 mmol/L ssDNA= 10.0 OD260 1 mmol/L ssRNA= 8.3 OD260 5. 质量与摩尔数
每对碱基的平均分子量(MW)是660 pg/pmol μg×(106pg/1μg)×(pmol/660pg)×(1/N)=pmol N 是核酸碱基对数 1 μg 1,000bpDNA = 1.52 pmol 1 μg pUC18/19DNA (2,688bp) = 0.57 pmol 1 μg pBR322 DNA(4,361bp) = 0.36 pmol 1 μg SV40 DNA(5,243bp) = 0.29 pmol 1 μg FX174 DNA(5,386bp) = 0.28 pmol 1 μg M13mp18/19DNA (7.250bp) = 0.21 pmol 1 μg l phageDNA (48,502bp) = 0.03 pmol
每个碱基的平均分子量(MW)是330 pg/pmol μg×(106pg/1μg)×(pmol/330pg)×(1/N)=pmol 6. 摩尔数与质量
每对碱基的平均分子量(MW)是660 pg/pmol pmol×N×(660pg/pmol)×(1μg/106pg)=μg 1 pmol 1,000bpDNA = 0.66 μg 1 pmol pUC18/19DNA (2,688bp) = 1.77 μg 1 pmol pBR322DNA (4,361bp) = 2.88 μg 1 pmol SV40 DNA(5,243bp) = 3.46 μg 1 pmol FX174DNA (5,386bp) = 3.54 μg 1 pmol M13mp18/19 DNA (7.250bp) = 4.78 μg 1 pmol l phageDNA (48,502bp) = 32.01 μg
每个碱基的平均分子量(MW)是330 pg/pmol pmol×N×(330pg/pmol×(1μg/106pg)=μg 7. 浓度 C (mmol/L orpmol/ml) = OD260/(0.01*N C (ng/ml) =OD260*MW/(0.01*N) MW — molecularweight; N —number ofbases; OD260 —absorbance at 260 nm 8. 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:
pmol ends = pmol DNA *number of cuts * 2
pmol ends = pmol DNA * (number of cuts *2 + 2) 1 μg 1,000bp DNA = 3.04 pmol ends 1 μg pUC18/19 DNA (2,688bp) = 1.14 pmol ends 1 μg pBR322 DNA (4,361bp) = 0.7 pmol ends 1 μg SV40 DNA (5,243bp) = 0.58 pmol ends 1 μg FX174 DNA (5,386bp) = 0.56 pmol ends 1 μg M13mp18/19 DNA (7.250bp) = 0.42 pmol ends 1 μg l phage DNA (48,502bp) = 0.06 pmol ends 10. 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 Protein 1 kb DNA = 333 amino acid ≈ 37k DaProtein 10,000 Da Protein ≈ 270 bp DNA 30,000 Da Protein ≈ 810 bp DNA 50,000 Da Protein ≈ 2701 bp DNA 100,000 Da Protein ≈ 27 kb DNA 12. 蛋白质质量与摩尔数的转换 100pmol的100kDa蛋白分子=10μg 100pmol的50kDa蛋白分子=5μg 100pmol的10kDa蛋白分子=1μg 100pmol的1kDa蛋白分子=100ng 13. DNA电泳基本参数
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