Specific release of Albutensins from bovine and human serum albumin

Bovine Albutensin (BA) and human Albutensin (HA) represent f(208–216) of bovine serum albumin (BSA) and f(210–218) of human serum albumin (HSA), respectively. The release of BA and HA was studied during tryptic digestion of serum albumins in solutions at different pH values. Specific release of either BA or HA was achieved by tryptic hydrolysis of serum albumins in 0.1 m NaH2PO4 solution adjusted to pH 3.5. Under these conditions, about 29–50% of the theoretical maximum of BA and 18–23% of the theoretical maximum of HA were released at high purity after 18 h digestion. Heat treatment of BSA (90 °C for 1–60 min) prior to tryptic hydrolysis (pH 3.5) did not improve the release of Albutensins. Under the same heating conditions, Albutensin from either BSA or HSA proved to be stable. Tryptic hydrolysates at pH 3.5 of serum albumins were submitted to simulated gastro-intestinal digestion. BA and HA were stable under peptic hydrolysis whilst they were almost completely hydrolysed by Corolase PP™.