1. Digestion of Casein by Trypsin
■ Proteases Enzymes:
Enzymes that catalyze the hydrolysis of pepide bonds of proteins.

2. Digestion of Casein by Trypsin
■ Exoproteases:
liberate amino acids by breaking peptide bonds starting from the end of the polypeptide chain.
-H2O

3. Digestion of Casein by Trypsin
■ Endoproteases:
break down peptide bonds from the interior of the polypeptide chain.
e.g. Trypsin and Pepsin.

4. Trypsin
A endoprotease enzyme found in the pancreatic juice which catalyzes the hydrolysis of peptide bonds formed from the carboxyl groups of basic amino acids,
L-Arginine
L-Lysine

5. Pepsin
is an endoprotease found in the stomach which catalyzes the hydrolysis of peptide bonds between aromatic amino acids;
Phenylalanine
Tyrosine
Tryptophan

6. Casien Free amino groups
*Principle
Trypsin
Casien Free amino groups
~NH3 + H.CHO ~NH.CH2O + H
(monomethylol)

7. Tube # 1 2 3 4 30 min. 37°C 5 min at 3000 rpm Casien (ml) 1 1 1 160 30 15 45 5 10 20 25 35 40 50 55
1% % % %
30 min.
37°C
Casien (ml)
Trypsin (ml)
TCA 12% (ml)
5 min at 3000 rpm

8. 0.1N NaOH 1 Va.a. VNaOH 2 Va.a. VNaOH 3 Va.a. VNaOH 4 Va.a. VNaOH 1%
2 drops ph.ph.
Supernatant
VNaOH
5 ml 40% HCOOH 2
Va.a.
0.8%
VNaOH 3
0.6%
Va.a.
VNaOH 4
0.5%
Va.a.
VNaOH

9. * Calculations ( N × V ) a.a. = ( N `× V `) NaOH
Na.a. = ( N `× V `) NaOH
Va.a.
Samar A. Damiati