327
( Sardina ocellata ), tested the stability and effect of proteinases on it and emphasized
the occurrence of chondroitin sulfate. The preparation of ichthylepidin, its nature
and amino acid composition are discussed elsewhere (Seshaiya et al. 1963 ). The
most characteristic feature of ichthylepidin in contrast to collagen is that it is not
converted to gelatin upon boiling with water. The content of neutral sugars, hexosamine and uronic acid in fi sh scales was measured by Kalyani ( 1997 ) as following
(g per 100 g dry weight): glucose 0.9–1.0; galactose 0.6; hexosamine 0.47–0.61 and
uronic acid 0.2.
Thus, collagens of fi sh origin (both marine and fresh water) are produced today
in large scales. Mostly these collagens are sources for gelatine production, however
there are some special fi elds of application of the collagens in pharmacy and biomedicine. For example, Chen et al. ( 2012 ) extracted a glycoprotein from the cartilage of blue shark ( Prionace glauca ) and identifi ed it as shark type II collagen (SCII).
The authors “aim to confi rm the effects of oral tolerance of SCII on infl ammatory
and immune responses to the ankle joint of rheumatoid-arthritis rats induced by
Complete Freund’s Adjuvant (CFA). [ The obtained ] results suggested that appropriate dose of SCII can not only ameliorate symptoms but also modify the disease
process of Complete-Freunds-Adjuvant-induced arthritis,” (Chen et al. 2012 ).
Fish Swimbladder Collagen The swimbladder of teleost fi shes is a gas-fi lled sac
which serves primarily to make the fi sh neutrally buoyant in sea water, but occasionally assumes other functions (see for review Davenport 2005 ; Tibbetts et al. 2007 ).
The gas contained in the swimbladder is largely oxygen, at a pressure very close to
the external hydrostatic pressure. The difference in gas partial pressure between the
gaseous contents of the swimbladder and the blood and tissue fl uids is large in fi sh
living at any considerable depth. The hydrostatic pressure increases about 1 atm
with each 10 m depth, while the partial pressures of gases in sea water and body
fl uids are relatively independent of depth and together give a pressure of only about
1 atm. The difference in partial pressure of oxygen alone across the wall of the
swimbladder of a fi sh living at 3,000 m depth is close to 300 atm (Wittenberg et al.
1980 ). Collagen is located within the membranous walls of fi sh swimbladder and
can be extracted using acetic acid (2.5 pH), and precipitated by the addition of NaCl
up to 3.0 M (see for details Fernandes et al. 2008 ).
Product known as isinglass is also of the fi sh swimbladder origin. Here, the
description of isinglass by Hickman et al. ( 2000 ):
“It is widely used commercially to clarify alcoholic beverages by aggregation of
the yeast and other insoluble particles. It is derived from swim bladders of tropical
fi sh by solubilisation in organic acids and consists predominantly of the protein collagen. The low content of intermolecular cross-links allows ready dissolution of
swim bladder compared to bovine hide; which is cross-linked by a high proportion
of stable bonds and requires enzymic digestion to solubilise. Isinglass is no longer
effective as a clarifying agent if thermally denatured hence the collagenous triple
helical structure must be maintained. Thermal denaturation of isinglass occurs at
29 °C, compared to 40–41 °C for mammalian collagens, primarily due to the lower
8.1 Isolation and Properties of Fish Collagens
( Sardina ocellata ), tested the stability and effect of proteinases on it and emphasized
the occurrence of chondroitin sulfate. The preparation of ichthylepidin, its nature
and amino acid composition are discussed elsewhere (Seshaiya et al. 1963 ). The
most characteristic feature of ichthylepidin in contrast to collagen is that it is not
converted to gelatin upon boiling with water. The content of neutral sugars, hexosamine and uronic acid in fi sh scales was measured by Kalyani ( 1997 ) as following
(g per 100 g dry weight): glucose 0.9–1.0; galactose 0.6; hexosamine 0.47–0.61 and
uronic acid 0.2.
Thus, collagens of fi sh origin (both marine and fresh water) are produced today
in large scales. Mostly these collagens are sources for gelatine production, however
there are some special fi elds of application of the collagens in pharmacy and biomedicine. For example, Chen et al. ( 2012 ) extracted a glycoprotein from the cartilage of blue shark ( Prionace glauca ) and identifi ed it as shark type II collagen (SCII).
The authors “aim to confi rm the effects of oral tolerance of SCII on infl ammatory
and immune responses to the ankle joint of rheumatoid-arthritis rats induced by
Complete Freund’s Adjuvant (CFA). [ The obtained ] results suggested that appropriate dose of SCII can not only ameliorate symptoms but also modify the disease
process of Complete-Freunds-Adjuvant-induced arthritis,” (Chen et al. 2012 ).
Fish Swimbladder Collagen The swimbladder of teleost fi shes is a gas-fi lled sac
which serves primarily to make the fi sh neutrally buoyant in sea water, but occasionally assumes other functions (see for review Davenport 2005 ; Tibbetts et al. 2007 ).
The gas contained in the swimbladder is largely oxygen, at a pressure very close to
the external hydrostatic pressure. The difference in gas partial pressure between the
gaseous contents of the swimbladder and the blood and tissue fl uids is large in fi sh
living at any considerable depth. The hydrostatic pressure increases about 1 atm
with each 10 m depth, while the partial pressures of gases in sea water and body
fl uids are relatively independent of depth and together give a pressure of only about
1 atm. The difference in partial pressure of oxygen alone across the wall of the
swimbladder of a fi sh living at 3,000 m depth is close to 300 atm (Wittenberg et al.
1980 ). Collagen is located within the membranous walls of fi sh swimbladder and
can be extracted using acetic acid (2.5 pH), and precipitated by the addition of NaCl
up to 3.0 M (see for details Fernandes et al. 2008 ).
Product known as isinglass is also of the fi sh swimbladder origin. Here, the
description of isinglass by Hickman et al. ( 2000 ):
“It is widely used commercially to clarify alcoholic beverages by aggregation of
the yeast and other insoluble particles. It is derived from swim bladders of tropical
fi sh by solubilisation in organic acids and consists predominantly of the protein collagen. The low content of intermolecular cross-links allows ready dissolution of
swim bladder compared to bovine hide; which is cross-linked by a high proportion
of stable bonds and requires enzymic digestion to solubilise. Isinglass is no longer
effective as a clarifying agent if thermally denatured hence the collagenous triple
helical structure must be maintained. Thermal denaturation of isinglass occurs at
29 °C, compared to 40–41 °C for mammalian collagens, primarily due to the lower
8.1 Isolation and Properties of Fish Collagens