Food Chemistry

16.2 Individual Constituents 755

Table 16.12.Proteinase inhibitors of aninal and plant origin

Inhibition ofa

Source/Inhibitor Molecular weight T CT P Bs AP SG PP

Animal tissues
Bovine pancreas
Kazal inhibitor 6153 + −−
Kunitz inhibitor 6512 ++−−−+
Chicken egg
Ovomucoid 27–31, 000 + −−
Ovoinhibitor 44–52, 000 ++− ++
Ficin-papain-inhibitor 12, 700 −−+ −
Plant tissues
Cruciferae
Raphanus sativusb 8–11, 200 + ±−++
Brassica junceab 10–20, 000 + ±
Leguminosae
Arachis hypogaeab 7500–17, 000 ++
Cicer arietinumb 12 , 000 ++
Glycine max
Kunitz inhibitor 21 , 500 ++−−
Bowman–Birk inhibitor 8000 ++− +
P. coccineusc 8800–10, 700 ++
P. lunatusc 8300–16, 200 ++−−±
P. vulgarisc 8–10, 000 ++−−
Pisum sativumb 8–12, 800 ++
Vicia fabab 23 , 000 ++
Convolvulaceae
Ipomoea batatasb 23–24, 000 + −−−−
Solanaceae
Solanum tuberosumb 22–42, 000 c ±±−±±±±
Bromeliaceae
Ananas comosusb 5500 ++
Gramineae
Hordeum vulgareb 14–25, 000 ±−−±±±
Oryza sativab ±−+
Secale cerealeb 10–18, 700 ++−
Triticum aestivumb 12–18, 500 ±−−
Zea maysc 7–18, 500 ++−
aT: trypsin, CT:α-chymotrypsin, P: papain, Bs: Bacillus subtilis proteases, AP: Aspergillus spp. proteases,

SG: Streptomyces griseus proteases, PP: Penicillium spp. proteases,+: inhibited,−: not inhibited,±: inhib-
ited by some inhibitors of the particular source.
bThe properties of different inhibitors are combined.
cSubunits 6–10,000.

16.2.3.2 Structure

Many proteinase inhibitors have been isolated
and their structures elucidated. The active center
often contains a peptide bond specific for the
inhibited enzyme, e. g., Lys-X or Arg-X in
trypsin inhibitors and Leu-X, Phe-X or Tyr-X

in chymotrypsin inhibitors (Table 16.13, 16.14).

In addition, inhibitors are known that inhibit

trypsin and chymotrypsin and contain only one

trypsin-specific peptide bond at the active center,

e. g., Kunitz inhibitors from bovine pancreas

and soybeans (cf. Table 16.14). Some double-

headed inhibitors contain two different active