It should be known for what purposes you add this to a protein. Is it for chross-linking or just fixation? Preliminary recommendations are: Either lower pH to to lowest possible in order to reduce activity of reactive groups in the protein of simply reduce concentration of the glutaraldehyde.

Yes I agree with the answer above. If you are trying to crosslink with GTA it will 1st react with the Lys residues so you could calc the no. of moles to add per lys residue in the protein working on a Lys:GTA of

Please optimize the concentration of glutaraldehyde by using different concentration from lower to higher level.

As you asked the quesiton in tissue engineering; I assume that you are trying to crosslink a scaffold. You can obtain a degree of control over the reaction by using glutaraldehyde vapor instead of immersion for the crosslinking.

I want to use it for crosslinking.(For a scaffold)u very much for your answers.

Thank you very much for your answers.

Best

Burcu

I have optimised it to 0.5% GLU for 2 hours for creating wonderful Lipase CLEA at RT.

if you wish to reduce cross-linking by glutaraldehyde then mix it with freshly prepared formaldehyde from paraformaldehyde (2% of each: called Karnovsky's fixative). This minimizes cross-linking and proportions used determine degree of cross-linking by glut.

Try to mix it with Phosphate buffered saline (PBS),I have used it before to fabricate Electro-chemical sensors cause I had to obtain different results for different concatenation of glutaraldehyde.I used same method and I got different responses .

You can prepare it by yourself :

NaCl 137( mmol/l )-----8.0(g/m)

KCl 2.7-------------------0.2

Na2HPO4 10---------------------1.44

KH2PO4 1.8--------------------0.24

I agree to the previous  suggestion that low the pH, it should work.