Activity of DNA Modifying Enzymes in rCutSmart™ Buffer

We are excited to announce that we are in the process of switching all reaction buffers to be BSA-free. Beginning April 2021, NEB will be switching our current BSA-containing reaction buffers (NEBuffer™ 1.1, 2.1, 3.1 and CutSmart® Buffer) to Recombinant Albumin (rAlbumin)-containing buffers (NEBuffer r1.1, r2.1, r3.1 and rCutSmart™ Buffer). We anticipate that this switch may take as long as 6 months to complete. We feel that moving away from animal-containing products is a step in the right direction and are able to offer this enhancement at the same price. Find more details at

During this transition period, you may receive product with BSA or rAlbumin-containing buffers. NEB has rigorously tested both and has not seen any difference in enzyme performance when using either buffer. Either buffer can be used with your enzyme. All website content will be switched in April to reflect the changes, although you may not receive the new buffer with your product immediately.

Enzyme Activity in rCutSmart Buffer Required Supplements*
Alkaline Phosphatase (CIP) +++  
Antarctic Phosphatase +++  Requires Zn2+
Bst DNA Polymerase +++  
CpG Methyltransferase (M. SssI) +++  
DNA Polymerase I +++  
DNA Polymerase I, Large (Klenow) Fragment
DNA Polymerase Klenow Exo- +++  
DNase I (RNase-free) +++ Requires Ca2+
E. coli DNA Ligase +++ Requires NAD
Exonuclease I
Exonuclease III +++  
Endonuclease III (Nth), recombinant +++  
Exonuclease V (Rec BCD)  +++ Requires ATP
Exonuclease VII +++
Endonuclease VIII  +++  
Fpg  +++   
GpC Methyltransferase (M. CviPI) + Requires DTT
Lambda Exonuclease  ++  
McrBC +++  
Micrococcal Nuclease +++ Requires Ca2+
phi29 DNA Polymerase +++ Requires DTT
Quick CIP +++  
RecJf +++  
rSAP +++  
T3 DNA Ligase +++ Requires ATP + PEG
T4 DNA Ligase +++ Requires ATP
Hi-T4™ DNA Ligase +++ Requires ATP
Salt-T4® DNA Ligase + Requires ATP
T4 DNA Polymerase +++  
T4 Phage β-glucosyltransferase (T4-BGT) +++  
T4 Polynucleotide Kinase +++ Requires ATP + DTT
T4 PNK (3 ' phosphatase minus) +++ Requires ATP + DTT
T5 Exonuclease  +++  
T7 DNA Ligase +++ Requires ATP + PEG
T7 DNA Polymerase (unmodified) +++
T7 Exonuclease +++  
Thermolabile ExoI +++
USER® Enzyme, recombinant

*Refer to “Reaction Conditions” on product webpage for recommended supplement concentration

+++ full functional activity
++ 50-100% functional activity
+ 0-50% functional activity