Liquid state NMR greatly benefits from Transverse Relaxation Optimized (TROSY) experiments that increase the sensitivity and the resolution of amide NH or aromatic CH pairs, methyl, trifluoromethyl or methylene groups. Among them, the CH2-TROSY has been largely underexploited so far, despite the large fraction of methylene-type hydrogens in biomolecules. This could be explained by the difficulty of isotopically labelling methylenes in a perdeuterated background whereas this is readily achievable for the popular NH and methyl TROSY. Here, we describe a cell-free protein expression protocol that allows specific glycine 13C-15N labelling of a subunit of the heavy-metal ATPase HMA8, whilst all other amino acids are perdeuterated 2H-15N. This technique enables us to eliminate a great fraction of amino acid scrambling and cross-protonation from the solvent resulting in high labelling selectivity. We show how the sample, recorded with CH2-TROSY experiments, improves the spectral quality of glycine residues in medium sized proteins. A titration experiment of a peptide ligand on the catalytic domain of the Pin1 protein demonstrates the benefit of this approach for ligand binding studies. Precise aliphatic CSP are obtained and can be used for Kd determination.