الفهرس 
acknowledgmentOnly 14 pages are availabe for public view
 |  | from | 80 |  |  |
| | | from | 80 | | |
Abstract
Different topics are clarified in this chapter as follows:
I. Proteolytic Enzymes
I’
Proteolytic enzymes are considered as group of hydrolyzing
enzymes that deal with hydrolysis of peptide bonds of protein and a
small or large peptide. Some enzymes do not require an adjacent
terminal carboxyl or amino group and may even be prevented from
acting by such groups while others require such a free terminal group.
The former termed endopeptidases which act in the middle of the
peptide chain breaking protein molecules up into smaller fragments. The
latter exopeptidases cannot hydrolyse link in the middle of the chain but
some act fromthe carboxyl and other from the amino end of the chain.U?
Endopeptidase and exopeptidase enzymes co-operate very
effectively in protein digestion in which the main function of the former
is to produce a large number of free ends at which the latter can act. On
the other hand, the endopeptidases are divided into sub-sub group on the
basis of the catalytic mechanism and enzyme active site as follows:
1- Serine - proteinases
This group of enzymes are so named because they characterized by
the possession of peculiarly reactive serine residue that is essential for
their enzymatic activity. These enzymes differ greatly in the specificity
of the reaction catalyzed but they all possess the common feature of
being able to catalyze the hydrolysis of esters (2), All of this enzymes
have an active and catalytically essential histidine as well as similar
kinetic mechanism (2) , The catalytically essential histidine and serine are
located at the substrate binding site together with invariant aspartic.