浓度换算公式

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核酸、核苷酸的基本换算
核酸、核苷酸的基本换算
1.核酸的换算:
(1)摩尔数与质量:1 μg 1,000bp DNA = 1.52 pmol
1 μg pUC18/19 DNA (2,688bp) = 0.57 pmol
1 μg pBR32
2 DNA (4,361bp) = 0.35 pmol
1 μg SV40 DNA (5,243bp) = 0.29 pmol
1 μg FX174 DNA (5,386bp) = 0.28 pmol
1 μg M13mp18/19 DNA (7.250bp) = 0.21 pmol
1 μg l phage DNA (48,502bp) = 0.03 pmol
1 pmol 1,000bp DNA = 0.66 μg
1 pmol pUC18/19 DNA (2,688bp) = 1.77 μg
1 pmol pBR32
2 DNA (4,361bp) = 2.88 μg
1 pmol SV40 DNA (5,243bp) = 3.46 μg
1 pmol FX174 DNA (5,386bp) = 3.54 μg
1 pmol M13mp18/19 DNA (7.250bp) = 4.78 μg
1 pmol l phage DNA (48,502bp) = 32.01 μg
(2)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 = 0.1
2 mmol/L
1 mmol/L dsDNA = 6.7 OD2601 mmol/L ssDNA = 10.0 OD2601 mmol/L ssRNA = 8.3 OD260 (3)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
(4)核酸末端浓度:
环状DNApmol ends = pmol DNA × number of cuts ×2线性DNApmol ends = pmol DNA
×(number of cuts ×2 + 2)
1 μg 1,000 bp DNA = 3.04 pmol ends
1 μg pUC18/19 DNA (2,688 bp) = 1.14 pmol ends
1 μg pBR32
2 DNA (4,361 bp) = 0.7 pmol ends
1 μg SV40 DNA (5,243 bp) = 0.58 pmol ends
1 μg FX174 DNA (5,386 bp) = 0.56 pmol ends
1 μg M13mp18/19 DNA (7.250 bp) = 0.4
2 pmol ends
1 μg l phage DNA (48,50
2 bp) = 0.06 pmol ends2.
核苷酸的换算:
(1)分子量:
MW (Da) = 333 × N (number of bases)
(2)浓度:
C (μmol/L or pmol/ml) = OD260 / (0.01 × N)C (ng/ml) = OD260? MW / (0.01 × N)MW -- molecular weightN -- number of basesOD260 -- absorbance at 260 nm
(3)双链DNA与寡核苷酸的熔点
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
(4)DNA与表达蛋白之间分子量换算
1 kb DNA = 333 amino acid ≈3.7 × 104 Da
10,000 Da Protein ≈ 270 bp DNA30,000 Da Protein≈ 810 bp DNA
50,000 Da Protein ≈2701 bp DNA100,000 Da Protein ≈ 27 kb DNA
DNA电泳基本参数
1.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
1,000~30,000 0.5% 100~1,000 3.5%
800~12,000 0.7% 80~500 5.0%
500~10,000 1.0% 60~400 8.0%
400~7,000 1.2% 40~200 12.0%
200~4,000 1.5% 5~100 20.0%
50~2,000 2.0%
2.变性、非变性PAGE胶中染料迁移率PAGE浓度溴酚蓝二甲苯青
(相当核苷酸片段大小,bp)
3.5% 100 460
5.0% 65 260
8.0% 45 160
12.0% 20 70
15.0% 15 60
20.0% 12 45。