Proteolytic enzymes, also known as proteases, degrade proteins through cleavage of peptide bonds. Common proteases include papain from papaya, bromelain from pineapple, pepsin in the stomach, trypsin in the pancreas, and rennin and cathepsins in lysosomes. These enzymes have various industrial and medical applications such as meat tenderizing, cell culture, cheese production, and protein digestion.

1. Proteolytic Enzymes

2. Proteolytic Enzymes
 Enzymes involved in degradation of
proteins are called as proteases or
proteolytic enzymes
 Industrially available proteolytic enzymes
produced by microorganisms are usually
mixtures of endopeptidases and
exopeptidases.
 Proteins Polypeptides
2
Endopeptidases
Exopeptidases

3. Cont …
 Because of the complex structures and high
molecular weights of proteins enzymic proteolysis
is extremely complicated.
 Most proteases are quite specific with regard to
which peptide linkages they can split
3

4. List of proteolytic enzymes
a. Papain
b. Ficain
c. Bromelain
d. Pepsin
e. Rennin
f. Cathepsin
g. Trypsin
4

5. A) Papain
◦ Found in papaya
◦ papain, also known as papaya proteinase I
◦ Broad pH (3-11) and temperature stability
 For this reason very popular for a variety of food
applications.
1. Used as a meat tenderizer on inferior meat cuts (can also use
slice of pineapple on meat)
 The enzyme makes its way into the muscle and
hydrolyzes primarily connective tissue proteins (collagen
etc.) and softens muscle
 Have to use low amount to prevent liquefaction of
muscle
 If you mix raw papaya into Jell-O it will not form a gel

6. Application of papain
 Meat Tenderizer- Papain ( a protease
found in papaya) is used as meat
tenderizer to soften meat for cooking

7. Cont…
 Papain can be used to dissociate cells
in the first step of cell
culture preparations.
7

8. Ficain
 Ficain also known as
ficin is an enzyme that is derived
from figs latex
 It is of a family of proteases known as
the cysteine endopeptidases
 It is one of the most commonly used for
differentiating many blood group antigens
8

9. Bromelain
 Bromelain is an enzyme generally found in the
stems and fruits of pineapples.
 According their sources enzymes are divided into
A. Stem bromelain.
B. Fruit bromelain.
 The proteolytic enzymes are sulfhydryl proteases,
since a free sulfhydryl group of a cysteine side
chain is required for function
9

10.  Bromelain is present in all parts of the
pineapple plant but the stem is the
most common commercial source
10

11. Applications of bromelain
 Along with papain, bromelain is one of the most
popular proteases to use for meat tenderizing
 Cooked pineapple does not have a tenderizing
effect, as the enzymes are heat-labile
 Preparation of meat balls
 Systemic enzyme therapy (combinations of
proteolytic enzymes such as bromelain, trypsin and
papain) has been used in the treatment of breast
cancer
11

12. Pepsin
 Pepsin is an enzyme whose zymogen (pepsinogen) is
released by the chief cells in the stomach and that degrades
food proteins into peptides
 It was discovered by Theodor Schwann who also coined its
name from the Greek word pepsis, meaning "digestion
 Pepsin is one of three principal protein-degrading enzyme in
the digestive system, the other two
being chymotrypsin and trypsin
 Pepsin is most efficient in cleaving peptide bonds and
preferably breaks at aromatic amino acids such
as phenylalanine, tryptophan, and tyrosine
12

13. Cont…
 Pepsin is most active in acidic environments Pepsin exhibits
maximal activity at pH 2.0 and is inactive at pH 6.5
 In most cases Pepsinogen is activated by HCl
 Pepsins should be stored at very low temperatures (between
−80 °C and −20 °C) to prevent autolysis (self-digestion
13

14. Applications of pepsin
 Pepsin is commonly used in the
preparation of F(ab')2 fragments from
antibodies
14

15. Cont…
 Powder of pepsin is often used as a
dietary supplement to aid digestion
15

16. Rennin
 Rennin or Chymosin is a protease produced by
newborn ruminant in the fourth stomach to curdle the milk
they ingest
 The native substrate of Chymosin is K-casein cleavaes at
amino acids like phenylalanine and methionine
 Bovine chymosin is now produced recombinantly in E.
coli, Aspergillus niger alternative resource.
16

17. Application of rennin
 It is widely used in the production
of cheese
17

18. Cathepsin
 Cathepsins are proteases that degrade proteins)
found in all animals as well as other organisms.
 Enzyme cathepsins found only in the lysosome
 Most of the members become activated at the low
pH found in lysosomes
18

19. Cont….
 There are approximately a dozen members
of this family, which are distinguished by
their structure
 Cathepsin A (serine protease)
 Cathepsin B (cysteine protease)
 Cathepsin C (cysteine protease)
 Cathepsin D (aspartyl protease)
 Cathepsin E (aspartyl protease)
 Cathepsin F (cysteine proteinase)
19

20. Trypsin
 Trypsin is a protease found in the digestive
system of many vertebrates, where
it hydrolyses proteins.
 Trypsin is produced in the pancreas as the inactive
protease trypsinogen.
 Trypsin cleaves peptide chains mainly at
the carboxyl side of the amino
acids lysine or arginine
20

21. Application of trypsin
 In a Animal tissue culture lab, trypsin is used to re-
suspend cells adherent to the cell culture dish wall
during the process of harvesting cells
 Used in proteomics experiments to digest proteins
into peptides for mass spectrometry analysis
 As a baking enzyme to improve the workability of
dough;
 in the extraction of seasonings and flavourings
from vegetable or animal proteins and in the
manufacture of sauces 21

22. Cont…
 To improve the texture of fish products
 To tenderize meat along with papain
 For cold stabilization of beer
22

23. Cont…
 In the production of hypoallergenic food where
trypsin break down specific allergenic proteins into
non allergenic peptides
23