Serum leucine-rich alpha-2-glycoprotein-1 binds cytochrome c and inhibits antibody detection of this apoptotic marker in enzyme-linked immunosorbent assay
- First Online:
- 269 Downloads
Cytochrome c (Cyt c) has been implicated as a serum marker for aberrant apoptosis and, thus, has considerable clinical potential. Using a sandwich enzyme-linked immunosorbent assay (ELISA) we found that the sensitivity of Cyt c detection is reduced in the presence of serum. The inhibitory factor responsible was purified from both fetal bovine serum and human serum employing standard chromatography procedures followed by affinity chromatography on Affi-Gel 10-bound Cyt c. In SDS-PAGE, bands at 44 kD and 50 kD were observed for the bovine and human proteins, respectively. Mass spectrometry analysis identified the serum inhibitory factor as leucine-rich alpha-2-glycoprotein-1 (LRα2GP1). This identification may lead to a modified ELISA to quantify total Cyt c in patients’ sera. LRα2GP1 is the first extracellular ligand for Cyt c that has been identified. A physiological function associated with binding is suggested.
KeywordsCytochrome c Apoptotic marker ELISA Leucine-rich alpha-2-glycoprotein-1 Leucine-rich repeats
basic local alignment search tool
bovine serum albumin
- Cyt c
enzyme-linked immunosorbent assay
- MALDI-TOF MS
matrix assisted laser desorption ionization time-of-flight mass spectrometry
polyacrylamide gel electrophoresis in sodium dodecylsulfate
Unable to display preview. Download preview PDF.