Glutathione secretion in buffalo milk and its gammaglutamyltransferase-mediated metabolism

The study examined the hypothesis that GSH is secreted into buffalo milk, and that some of the secreted GSH is degraded by the enzyme gamma-glutamyltransferase (GGT) within the milk space. The data confirmed such hypothesis and, together with previous studies concerning the presence of GSH synthetic and catabolic enzymes in mammary tissue, suggest that the buffalo mammary gland may have a functional gamma-glutamyl cycle. Such cycle probably contributes to the secretion of cysteine - a fundamental amino acid for neonatal growth and development- into buffalo milk.