Glutamine
Glutamine is the most abundant amino acid in the blood and a ready source of glutamate, one of glutathione's three building blocks. Cells convert it to glutamate with the enzyme glutaminase.
Also called L-glutamine, Gln.
In growth-plate cartilage during bone development, studied in animals and in cells, chondrocyte identity was tied to glutamine use: SOX9, the master switch of cartilage cells, raised their glutamine uptake and their levels of glutaminase 1, the enzyme that controls its breakdown (Stegen 2020).
Glutamine did three jobs there: it helped switch on cartilage genes, supported cell division and matrix production, and fed glutathione synthesis, which kept reactive oxygen species down so the cells could survive without a blood supply (Stegen 2020).
In rabbit cartilage cells in the lab, glutamine almost completely prevented cell loss from heat stress and nitric oxide, an effect linked to the protective protein HSP70 (Tonomura 2006).
Sources
- Stegen S, Rinaldi G, Loopmans S et al. Glutamine Metabolism Controls Chondrocyte Identity and Function. Dev Cell 2020.
- Tonomura H, Takahashi KA, Mazda O et al. Glutamine protects articular chondrocytes from heat stress and NO-induced apoptosis with HSP70 expression. Osteoarthritis Cartilage 2006.
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