It is also possible to produce half-cystine
residues for disulfide cross-links by placing the half-cystine
residues in the correct primary sequence, and then adjusting the length of the bisulfide bond between these residues.
Concentrations of half-cystine, lysine, ornithine, and arginine in AF (Fig.
Cystinuria was confirmed by urine amino acid chromatography (half-cystine, ornithine, lysine and arginine concentrations >10 times the upper limit of the reference interval), thus excluding transient hyperexcretion of cystine in the first months of life as an explanation (5).