IgG is the most abundant of the 5 classes of immunoglobulins, representing about 80% of the serum immunoglobulin proteins. It is the major antibody of secondary hormonal answer of immunity. IgG is the smallest (150kd) of the five classes of antibodies and contains 2% carbohydrate. IgG molecule comprises of cardinal different polypeptide chains, twain knockout chains and two sporting chains linked together by disulfide bonds. The variable regions of the heavy and light chain are specific for a lawsuit of antigen. Each antigen is thus bivalent and able to attach to two antigenic sites, there are millions of possible types of igG thence why it is called variable. The constant regions are highly specific as all humans make identical forms; it determines the antibody class, igG, igE, igD, IgM and immunoglobulin A as this part is the same within each class.
The mythic mete out of the antibody has specificity of binding an epitope of an antigen. The fc portion directs the biological activity of the antibody. The fc portion potbelly bind to phagocytes and enhances attachment (sponization) as well as activate the complement pathway.
IgG is present equally in the blood stream and the tissues. IgG levels in the blood are usually between 7-15g/L.
It is the only class of antibody that crosses the placenta. This is because IgG exists as a monomer and is only one both small complete to cross the placenta and found in large enough cadence in plasma to make it in a measurable level to the fetus.
The mother igG protects the fetus and infant as a newborn until around 9months when it will have connatural concentration of antibody as mum and the infants immune system can produce its own antibodies.
The Fc recognizes the constant heavy chain and the sense organ binds, this allows it to cross the placenta.
The hinge region can provide flexibility for antibodys to bind two separate but identical antigenic structures or epitopes with various distances to...If you want to get a wide-eyed essay, order it on our website: Orderessay
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