Protein aggregation--pathways and influencing factors.

Proteins generally will tend to aggregate under a variety of environmental conditions in comparison with small drug molecules. The extent of aggregation is dependent on many factors that can be broadly classified as intrinsic (primary, secondary, tertiary or quaternary structure) or extrinsic (environment in which protein is present, processing conditions, etc). These protein aggregates may exhibit less desirable characteristics like reduced or no biological activity, potential for immunogenicity or other side effects. Protein aggregation remains one of the major challenges in the development and commercialization of biotechnology products. This article is intended to review and discuss the latest understandings in protein aggregation pathways and the possible extrinsic factors that affect or control the protein aggregation process. Copyright 2010 Elsevier B.V. All rights reserved.