STM Article Repository

Background: Ovomucoid is a serine proteinase inhibitor in the egg whites of all avian species at a
concentration of about 10 mg/ml. The involvement of proteinases in a multitude of control functions in
an organism has created an interest in their physiological inhibitors. Regulation of proteolytic activity
in tissues is a critical requirement in the maintenance of homeostasis. Egg white proteins possess
ACE-inhibitory activity & high radical-scavenging activity. The combined antioxidant and ACEinhibitory
properties of egg white hydrolysates, or the corresponding peptides would make a useful
multifunctional preparation for the control of cardiovascular diseases. Proteases play key roles in
several physiological processes, including intracellular protein degradation, bone remodeling, and
antigen presentation, and their activities are increased in pathophysiological conditions such as,
cancer metastasis and inflammation. They are also required for invasion by the microorganism. Four
protease inhibitors have been identified in egg white namely, cystatin, ovomucoid, ovomacroglobulin
(also known as ovostatin), and ovoinhibitor. Use of proteinase inhibitors in the treatment of certain
diseases has renewed interest in their specificity and stability, both of which in turn depend on the
tertiary structure of the inhibitor. Structural alteration to obtain molecules of desired properties
requires knowledge of relationship between structure, function and stability.
Aims: Given its importance, in the present study duck ovomucoid was isolated and characterized for
its physicochemical properties.
Methodology: Duck ovomucoid was isolated and characterized by its physicochemical properties.
Analytical gel filtration (Sephacryl S-100 HR column) was used for purification, determination of
molecular weight (MW), carbohydrate content and Stokes radius.
Results & Conclusion: The fluorescence emission spectrum was 302 nm, comparable to earlier
reports. Stoke’s radius was found to be 2.91nm, and the value was comparable with white leghorn
hen (Stoke’s radius 3.15nm). The extraordinary large value of stokes radius can be attributed to its
high carbohydrate content which increases the hydration of the molecule. The inhibitor had the
molecular weight of 29,300, and the carbohydrate content was 22%, the specific extinction coefficient
of duck ovomucoid was found to be 5.82 at 279 nm and the Stoke’s radius was 2.91nm. The
extraordinary large value of stokes’ radius of duck ovomucoid can be attributed to its high
carbohydrate content which increases the hydration of the molecule resulting in large Stoke’s radius.
Further functional studies on duck ovomucoid are required, as it has been reported that the chicken
ovomucoid hydrosylates have some exceptional antioxidant, ACE inhibitory and metal chelating
activities.