Protein Microheterogeneity

Polypeptides separated by 2D-PAGE rarely appear as single spots, and most are resolved as multiple spots characterized by charge and size microheterogeneities (Figure 2).

Microheterogeneity is due to several factors that frequently occur together. The first cause of micro-heterogeneity is genetic polymorphism where heterozygote individuals express both forms of the gene (Figure 3); the second is related to protein co- and post-translational modifications. These modifications are multiple and have all the potential of modifying a protein's charge, hydrophobicity, conformation and/or stability. Furthermore, the 'one gene one poly-peptide' paradigm is challenged by the alternative splicing of many genes responsible for synthesizing several proteins from a single gene. An important feature of 2D gel analysis is that various protein isoforms generated by co- and/or post-translational modifications can be separated by isoelectric focusing and/or by SDS-PAGE. Among the modifications which lead to a charge-dependent change to a protein, acylation, alkylation, carboxymethylation, phosphorylation, sulfation, carboxylation, sialylation and proteolytic processing are involved. Finally, glycosylation of proteins may lead to both charge and size modifications, and microheterogeneity of a protein may reflect the presence of several glyco-forms.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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