N Mix CPG (5'-DMT-[dA(Bz), dC(Ac), dG(dmf), T]-Glyc-CPG); 1000 Å is a reagent used in the solid-phase synthesis of oligonucleotides to incorporate a randomized mixture of the four nucleosides: deoxyadenosine (dA) with benzoyl (Bz) protection, deoxycytidine (dC) with acetyl (Ac) protection, deoxyguanosine (dG) with dimethylformamidine (dmf) protection, and thymidine (T). The nucleosides are attached via a glycolate (Glyc) linker to controlled pore glass (CPG) with a 1000 Å pore size. This reagent is typically used in the synthesis of random-sequence oligonucleotides, allowing for the generation of diverse sequence libraries with each position having an equal probability of being any of the four bases. The 5'-DMT group protects the 5' end during synthesis, ensuring efficient and accurate oligonucleotide construction. Mixed base supports are used to create dNTP oligos used for mutation studies.