Structural analysis of cartilage proteoglycans and glycoproteins using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Cartilage extracellular matrix molecules synthesized and maintained by chon drocytes form a strong, elastic tissue functioning to cushion and protect t he subchondral bone, Osteoarthritis is characterized by degradation of cart ilage extracellular matrix molecules resulting in fibrillation, irreversibl e erosion, and eventual failure of the tissue. With recent interest in the degradation of cartilage extracellular matrix molecules, a need for more de tailed structural information exists. Posttranslational modifications are b elieved to play a role in determining the susceptibility of these molecules to proteolytic degradation during the development of osteoarthritis. The p urpose of this paper is to show how the application of matrix-assisted lase r desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry to ext racellular matrix protein and proteoglycan structure will help elucidate pr oblems in extracellular matrix biochemistry. Methodological issues relating to the high molecular weight, polydispersity, and high degree of posttrans lational modification of these molecules are discussed. MALDI-TOF mass spec trometry provides an improved level of detail for extracellular matrix prot ein and proteoglycan structure and is useful in addressing issues surroundi ng the causes of degradation during osteoarthritis, (C) 2000 Academic Press .