一,SpectrophotometricConversions1A260unitofdouble-strandedDNA=50µg/ml1A260unitofsingle-strandedDNA=33µg/ml1A260unitofsingle-strandedRNA=40µg/ml二,DNAMolarConversions1µgof1,000bpDNA=1.52pmol(3.03pmolofends)1µgofpBR322DNA=0.36pmolDNA1pmolof1,000bpDNA=0.66µg1pmolofpBR322DNA=2.8µg三,FormulasforDNAMolarConversions1,FordsDNAToconvertpmoltoµg:pmol×N×660pg/pmol×1µg/106pg=µgToconvertµgtopmol:µg×106pg/1µg×pmol/660pg×1/N=pmol2,ForssDNAToconvertpmoltoµg:pmol×N×330pg/pmol×1µg/106pg=µgToconvertµgtopmol:µg×106pg/1µg×pmol/330pg×1/N=pmol#whereNisthenumberofnucleotidesand330pg/pmolistheaverageMWofanucleotide四,ProteinMolarConversions100pmolof100kDaprotein=10µg100pmolof50kDaprotein=5µg100pmolof10kDaprotein=1µg100pmolof1kDaprotein=100ng五,Protein/DNAConversions1kbDNA=333aminoacids=37kDaprotein270bDNA=10kDaprotein810bDNA=30kDaprotein1.35kbDNA=50kDaprotein2.7kbDNA=100kDaprotein#averageMWofanaminoacid=110daltons#Dalton(Da)isanalternatenamefortheatomicmassunit,andkilodalton(kDa)is1,000daltons.Thusaproteinwithamassof64kDahasamolecularweightof64,000gramspermole六,AgaroseGel(%):ResolutionofLinearDNARecommended%Agarose----OptimumResolutionforLinearDNSizeoffragmentsinnucleotides;bp0.5---------------1,000-30,0000.7---------------800-12,0001.0---------------500-10,0001.2---------------400-7,0001.5---------------200-3,0002.0----------------50-2,000七,PolyacrylamideGel(%):ResolutionofProteinRecommended%Acrylamide---------ProteinSizeRange8----------------------40-200kDa10----------------------21-100kDa12-----------------------10-40kDa八,Length/M.W.ofCommonNucleicAcids.NucleicAcid------NumberofNucleotides---------MolecularWeightlamBDaDNA------48,502(dsDNA)------------3.2×107pBR322DNA------4,361(dsDNA------------2.8×10628SrRNA---------4,800---------------1.6×10623SrRNA(E.coli)-----2,900---------------1.0×10618SrRNA--------1,900----------------6.5×10516SrRNA(E.coli)-----1,500--------------5.1×1055SrRNA(E.coli)-----120----------------4.1×104tRNA(E.coli)---------75----------------2.5×104#Molecularweightsbasedonactualsequence.九,Stardards1.AverageMWofdsDNAbasepair=600.2.AverageMWofssDNAbase=330.3.AverageMWofRNAbase=340.[iframe][/iframe]