What is the proper concentration for a routine PCR reaction? March 10, 2021 09:01 For up to 3 kb, we recommend 1.25 units per 50 µl reaction For specialized applications, including 3–8 kb amplicons, 2.5 units per 50 µl reaction is recommended Related articles What is the concentration of protein that you usually get from E.coli expression system? Do you accept AUD (australia dollar) for payment?