Xiangming Fang, Lei Huang, Jerald S. Feitelson and Wei-Wei Zhang
GenWay Biotech, Inc, 10130 Sorrento Valley Road, Suite C, San Diego, CA 92121, USA
Drug Discovery Today: Technologies, 2004, 1: 141-148.
Abstract
A major challenge in protein target discovery and validation is how to specifically dissect complex protein mixtures and measure trace targets. Immunoaffinity-based protein capture, separation and detection have proven to be one of the most effective approaches. Avian IgY antibody microbeads (Seppro™), representing a type of novel and specific protein sorbent, have several distinct advantages over IgG. Their utility and applications are compared with those of IgG and other affinity reagents.
Section Editors: Luis Menéndez-Arias - CSIC-UAM, Madrid, Spain; Pierre Chatelain - UCB S.A., Braine-L'Alleud, Belgium; Bernard Masereel - University of Namur, Namur, Belgium
The authors discuss the key technologies for separating and dissecting protein mixtures using immunoaffinity-based methods. The review gives a detailed comparison of the IgG and IgY immunoglobulins for immunoaffinty-mediated separation. The authors also comment on other affinity separation technologies including antibody fragments and protein reagents.
Glossary:
1DE or 2DE
one or two-dimensional gel electrophoresis, methods commonly used for separating and analyzing protein mixtures. 1DE can be denaturing to measure molecular mass [sodium dodecyl sulfate poly-acrylamide gel electrophoresis (SDS-PAGE)], or non-denaturing, measuring protein complexes. 2DE contains the 1st dimension of isoelectric focusing and the 2nd dimension of SDS-PAGE.
Abundant protein removal
it is a challenge in proteomic profiling to discover low-abundant proteins in a given protein mixture. The abundant proteins are often 6-10 orders of magnitudes more concentrated than low abundant proteins. Thus, high abundant proteins must be removed to detect and measure trace proteins of medical importance.
Dynamic range of protein concentration
the variation in protein concentration from the most to the least abundant in a given protein mixture. A large range causes significant difficulties in proteomic profiling due to the limited detection range of currently available methods or instruments, normally several orders of magnitude less than the dynamic range of protein concentration.
IgG
immunoglobulin G, antibodies produced by mammalian or other vertebrate species mainly circulating in blood, frequently used in laboratories as affinity regents to capture, separate and detect protein targets.
IgY
immunoglobulin yolk, IgG-like antibodies isolated from egg yolks of immunized birds or other amphibians. IgY antibodies, having highly glycosylated and distinct constant (Fc) and shorter hinge regions than IgG, are viewed as ancestral to IgGs.
Immunoaffinity
specific molecular recognition and binding between antibodies or antibody-derived reagents and their target proteins. Immunoaffinity separation of proteins is a special type of affinity-based protein capture and separation.
Pre-fractionation
a process to separate a mixture of proteins into different fractions to enrich or remove certain proteins in the original mixture. It also refers to the preparing a protein mixture for further analysis.
Protein separation
distinct from protein "depletion", separation emphasizes in the context of abundant protein removal the ability to analyze both the protein sets captured by an affinity matrix as well as the unbound material that flows through the matrix.
Seppro™
IgY-microbeads for protein separation. Antigen affinity purified IgY antibodies covalently linked in an oriented fashion to microbeads through their Fc regions. | 
