The intestinal absorption of seaprose S(SAP), a microbial serme proteinase produced by A spergillus melleus, was studied using N-acetyl-L-tyrosine α-naphthyl ester (ATNE) as substrate.This substrate was highly susceptible to SAP, and with it, the minimum detectable concentration of SAP was about 0.01μg.
In experiments on intestinal absorption, sodium dodecylsulfate (SDS) was added to the assay system at a final concentration of 0.1%, since at this concentration it inhibited almost of the endogeneous ATNE-hydrolytic activity in rabbit serum, but only about 50%of that of SAP, and thus permitted measurement of SAP concentration in blood.
ATNE-hydrolytic activity of SAP in peripheral blood was detected in the range of intestinal administration of 10-100mg per kg of rabbit.
The results of gel filtration on Sephadex G-200 of the serum after intestinal administ-Iration showed that ATNE-hydrolytic activity was present in void fraction, indicating that SAP after intestinal absorption was probably trapped by a-macroglobulin, since in theresult of gel filtration on Sephadex G-200 of the mixture of serum and SAP ATNE-hydolytic activity was also eluted in void fraction.
These results sugges tthat SAP is absorbed in active formfrom intestine.
View full abstract