| 核酸、核苷酸的基本换算 | |
| 一、核酸的换算 | |
| 1、 摩尔数与质量 | |
| 1 μg 1,000bp DNA = 1.52 pmol | 1 pmol 1,000bp DNA = 0.66 μg |
| 1 μg SV40 DNA (5,243bp) = 0.29 pmol | 1 pmol M13mp18/19 DNA (7.249bp) = 4.78 μg |
| 1 μg FX174 DNA (5,386bp) = 0.28 pmol | 1 pmol SV40 DNA (5,243bp) = 3.46 μg |
| 1 μg lambda phage DNA (48,502bp) = 0.03 pmol | 1 pmol pUC18/19 DNA (2,686bp) = 1.77 μg |
| 1 μg M13mp18/19 DNA (7.249bp) = 0.21 pmol | 1 pmol pBR322 DNA (4,361bp) = 2.88 μg |
| 1 μg pBR322 DNA (4,361bp) = 0.35 pmol | 1 pmol lambda phage DNA (48,502bp) = 32.01 μg |
| 1 μg pUC18/19 DNA (2,686bp) = 0.57 pmol | 1 pmol FX174 DNA (5,386bp) = 3.54 μg |
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| 2、 光吸收值与浓度 | 3、 分子量 |
| 1 OD260 dsDNA = 50 mg/ml | 1个脱氧核糖核酸碱基的平均分子量为333 Daltons |
| 1 OD260 ssDNA = 33 mg/ml | 1个核糖核酸碱基的平均分子量为340 Daltons |
| 1 OD260 ssRNA = 40 mg/ml | |
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| 4、核酸末端浓度 | 二、核苷酸的换算 |
| 线性DNA：pmol ends = pmol DNA ′ (number of cuts ′ 2 + 2) | 1、 分子量 |
| 环状DNA：pmol ends = pmol DNA ′ number of cuts ′ 2 | MW (Da) = 333 ′ N (number of bases) |
| 2、 浓度 |
| 1 μg 线性1,000bp DNA = 3.04 pmol ends | C (mmol/L or pmol/ml) = OD260 / (0.01 ′ N) C (ng/ml) = OD260 ′ MW / (0.01 ′ N) |
| 1 μg 线性 FX174 DNA (5,386bp) = 0.56 pmol ends | 注：MW —— molecular weight；N —— number of bases；OD260 —— absorbance at 260 nm |
| 1 μg 线性 pUC18/19 DNA (2,686bp) = 1.14 pmol ends | 注： N —— 引物的长度(以碱基数计算)；J+ —— 单价阳离子浓度 |
| 1 μg 线性 SV40 DNA (5,243bp) = 0.58 pmol ends | 3、 双链DNA与寡核苷酸的熔点： |
| 1 μg 线性 pBR322 DNA (4,361bp) = 0.7 pmol ends | 短于20bp的双链寡核苷酸：Tm = 2 (A + T) + 4 (G + C) |
| 1 μg 线性 lambda phage DNA (48,502bp) = 0.06 pmol ends | 长于20bp的双链寡核苷酸： Tm = 81.5 + 16.6 ( lg[J+] ) + 0.41 (%GC) –(600/N) |
| 1 μg 线性 M13mp18/19 DNA (7.249bp) = 0.42 pmol ends | 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 DNA 30,000 Da Protein ≈ 810 bp DNA |
| 50,000 Da Protein ≈ 1350 bp DNA 100,000 Da Protein ≈ 2700 bp DNA |
