In general, the advantages of William E -MAX over Regular William E are as follows:

  1. Higher PH Capacity
  2. Contains 2 mM L-Alanyl-L-Glutamine (0.434g/L) instead of L-Glutamine and therefore:
  • Possess longer shelf life.
  • Minimizes toxic ammonia build-up.
  • Improves cell viability and growth.
  • Remains stable across a wide range of temperatures.
  • Minimizes the growth of pathogens by stabilizing the PH.
  • Improves the culture of primary cells.

Additionally, WILLIAM E -MAX contains:

  • 2 mM L-Alanyl-L-Glutamine (0.434 g/L) (therefore possess longer shelf life)
  • Non-Essential Amino Acids
  • Sodium Bicarbonate (2.2g/L)
  • 0.5 mM sodium pyruvate
  • Phenol Red
  • PurMa Biologics Manufactures several types of WILLIAM E  -MAX based on the amount of Sodium Bicarbonate and HEPES (PH capacity) requested (please visit

L-glutamine is a vital amino acid that is supplemented with mammalian cell culture media. This important amino acid has several important functions including the production of purine and pyrimidine nucleotides amino sugars, and glutathione as well as performing as the secondary source of energy. The latter is more crucial in cells dividing rapidly. Generally, this amino acid is used in cell culture media in the range of 2–6 mM.

One drawback of using L-glutamine is that in solutions such as cell culture media, L-glutamine degrades, resulting in the generation of toxic ammonia and pyrrolidine carboxylic acid. The speed of degradation of L-glutamine depends on time, temperature, and pH. One way to minimize the degradation of L-glutamine degradation in media is to gradually add these amino acids to your cell culture but has to be calculated to keep the level of L-glutamine at a constant level. Practically, this strategy even though is possible but tedious, and depending on the volume of cell culture work in your lab, keeping track of time to keep the level of L-glutamine at the same level is difficult and could be tedious if not impossible.

A viable and well-proven alternative for L-glutamine is L-alanyl-L-glutamine. This is less sensitive to environmental factors such as pH and therefore, is more stable in aqueous solutions. When L-alanyl-L-glutamine is used, cells gradually release aminopeptidases that hydrolyze the dipeptide. Consequently, L-alanine and L-glutamine are released slowly into the culture media and will be accessible for a much longer time. The resulting L-glutamine and L-alanine are then used by the cells for protein production or in the TCA cycle. PurMaTM GluaSup (Cat# P3S210559) contains L-alanyl-L-glutamine. PurMaTM GluaSup maximizes energy metabolism and high growth yield. Also, in the presence of PurMaTM GluaSup, ammonia in cells gets neutralized. The trace of toxic effect of ammonia in cell culture is inevitable when L-glutamine is used. PurMa Biologics also offers WILLIAM E -MAX with even higher buffering capacity; PurMaTM WILLIAM E -MAX 15 mM HEPES (3.6 g/L) (Cat No: P3M126106). More buffering capacity maintains physiological pH more efficiently.  An extra buffering system in this media is a powerful tool to avoid changing the PH which results in instability in growing and cellular mechanisms. Changing the PH is also one of the most common factors for growing mold and other pathogens. WILLIAM E -MAX functions better than regular WILLIAM E  on primary cell culture and most of the commercial cell lines such as MDCK, glial cells, fibroblasts, human endothelial cells, and rat fibroblasts. WILLIAM E -MAX contains no proteins, lipids, or growth factors. Therefore, it requires supplementation, commonly with 10-15% Fetal Bovine Serum (FBS).

Formulation: For complete formulation click here:William E-MAX Formulation

Parameter Specification
Appearance Red, clear liquid
pH 7.2 ± 0.1
Osmolality 275-360 mOsm/L
Endotoxin NMT< 2EU/mL
Mycoplasma Negative
Suitability  Suitable for mammalian cell culture
Additive Sodium pyruvate
Indicator Phenol red
Mycoplasma Detection Negative
Sterility Tested Sterile filtered using 0.22 µm filter
Form Liquid
Shipping Condition  Room temperature