Blood proteins

Immunoglobulins (Ig)

proteins produced by B lymphocytes as part of the humoral immune response to non-self molecules

Fab

the antigen-binding fragment of an immunoglobulin generated by Papain digestion

Fc

the crystal fragment of an immunoglobulin that cannot bind antigen but can bind and activate immune cells and complement

IgA

an immunoglobulin class found in the intestinal tract

IgD

an immunoglobulin class that acts as a cell-surface receptor on B lymphocytes

IgE

an immunoglobulin class found in minute quantities in serum that is involved in the response to parasites and in the allergic response

IgG

the major class of immunoglobulin in serum that can cross the placenta via receptor-mediated endocytosis

IgM

the first immunoglobulin class to be raised

Opsonisation

the process of labelling for phagocytosis utilizing the Fab and Fc regions

Epitope

an antigenic determinant that is represented by atoms in contact with the heavy and light chains

Nanobodies

single-domain

Myoglobin (Mb)

a protein that binds O2 in the muscle and acts like a store or sponge

Haemoglobin (Hb)

a tetramer protein that binds O2 and acts as a carrier in the blood

Haem

a prosthetic group consisting of Fe2+ in a protoporphyrin IX ring

Metmyoglobin

the Fe3+ form of myoglobin that cannot bind oxygen

p50

the pO2 level at which half of the myoglobin molecules are bound to O2

Deoxy Hb

the tense (T) form of haemoglobin that features low oxygen affinity

Oxy Hb

the relaxed (R) form of haemoglobin that features high oxygen affinity

Hill plot

a log/log graph used to display binding characteristics and cooperativity

2

3-Bisphosphoglycerate (2

Bohr shift

the phenomenon where increased H+ and CO2 concentrations reduce haemoglobin's oxygen affinity

Carboxyhaemoglobin

the all-R form of haemoglobin resulting from carbon monoxide binding

Methaemoglobinaemia

a condition causing blue skin resulting from an inherited deficiency of methaemoglobin reductase and the oxidation of haem to the Fe3+ form

Haemoglobin S (HbS)

an abnormal haemoglobin caused by a point mutation (Glu to Val) that distorts red blood cells and polymerizes to form long filaments in sickle cell anaemia

Thalassaemias

diseases characterized by a lack of one or the other subunit (alpha or beta) of haemoglobin

Haemoglobin F (HbF)

fetal haemoglobin which consists of two alpha and two gamma subunits