Related Experiment Videos
Characterisation of a slow component of normal human serum albumin
S O Brennan1, P M George, R J Peach
1Department of Clinical Biochemistry, Christchurch Hospital, New Zealand.
Abstract:
A minor component of albumin was isolated from normal human serum. It had reduced electrophoretic mobility, reacted normally with specific albumin antiserum and, in contrast to normal albumin, did not bind nickel. Sequence analysis showed that the minor band contained components with Ala-His-Lys- and His-Lys- N-terminal sequences, indicating removal of Asp and Asp-Ala respectively from the parent albumin which was found to have the expected N-terminal sequence of Asp-Ala-His-Lys. Both normal albumin and the minor component had an average of 0.32 residues of glucose bound as fructosamine.
Insights
A minor albumin component in human serum lacks nickel-binding ability due to N-terminal modifications. This modified albumin, despite sequence changes, retains normal antibody reactions and similar glucose binding.
Area of Science:
- Biochemistry
- Proteomics
- Human Physiology
Background:
- Albumin is the most abundant protein in human serum, crucial for maintaining osmotic pressure and transporting various molecules.
- Post-translational modifications of proteins can alter their function and properties.
- Understanding serum protein heterogeneity is important for diagnostics and understanding physiological processes.
Purpose of the Study:
- To characterize a minor, electrophoretically distinct component of normal human serum albumin.
- To investigate the structural and functional differences between normal albumin and this minor component.
- To identify the N-terminal sequence and nickel-binding properties of the minor albumin component.
Main Methods:
- Isolation of a minor albumin component from normal human serum.
- Electrophoresis to assess mobility.
- Immunological reaction with specific albumin antiserum.
- Nickel-binding assays.
- N-terminal amino acid sequencing.
Main Results:
- A minor albumin component with reduced electrophoretic mobility was isolated.
- This component reacted normally with albumin antiserum but did not bind nickel.
- Sequence analysis revealed N-terminal sequences of Ala-His-Lys- and His-Lys-, indicating removal of Asp and Asp-Ala from the parent albumin.
- Both normal albumin and the minor component exhibited similar levels of glucose bound as fructosamine (0.32 residues).
Conclusions:
- The minor albumin component represents a modified form of serum albumin with altered N-termini.
- The observed N-terminal modifications are associated with a loss of nickel-binding capacity.
- Despite structural differences, the minor component shares functional similarities with normal albumin regarding antibody recognition and glycation levels.