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Chromatographic behavior of immunoglobulin-bound creatine kinase on DEAE-Sephadex A-50
Insights
Macro-CK, a complex of creatine kinase (CK) isoenzymes bound to immunoglobulins, was analyzed using ion-exchange chromatography. This study identified IgA as the immunoglobulin in most macro-CK cases, with one case identified as IgM.
Area of Science:
- Biochemistry
- Clinical Chemistry
- Immunology
Background:
- Macro-CK, a complex of creatine kinase (CK) isoenzymes bound to immunoglobulins, can interfere with CK isoenzyme analysis.
- Understanding the chromatographic behavior of macro-CK is crucial for accurate diagnosis and interpretation of CK levels.
Purpose of the Study:
- To investigate the chromatographic behavior of CK isoenzymes and immunoglobulin-bound macro-CK using discontinuous gradient elution.
- To identify the specific immunoglobulin involved in macro-CK complexes in patients.
Main Methods:
- Discontinuous gradient elution from DEAE-Sephadex A-50 at pH 7 and 8 was employed.
- Chromatographic elution patterns of macro-CK were analyzed.
- Immunoglobulin elution patterns (IgG, IgM, IgA) were compared to macro-CK patterns.
Main Results:
- In four of five patients, macro-CK eluted similarly to IgA, with a significant portion shifting at pH 7.
- In the fifth patient, macro-CK eluted similarly to IgM at both pH values.
- IgG and IgM showed distinct elution patterns, while IgA exhibited pH-dependent behavior similar to macro-CK.
Conclusions:
- The immunoglobulin involved in macro-CK was identified as IgA in four patients and IgM in one patient.
- Chromatographic analysis at different pH values effectively differentiates macro-CK types based on their immunoglobulin components.
Abstract:
We investigated the chromatographic behavior of CK isoenzymes and immunoglobulin-bound macro-CK by discontinuous gradient elution from DEAE-Sephadex A-50 at pH 7 and 8. In four of five patients with macro-CK, the macro-CK was eluted with the MB buffer at pH 8, but a significant portion of the complex was eluted with the MM buffer at pH 7, in a region between CK-MM and CK-MB. In the fifth patient, the macro-CK was eluted with the MB buffer at both pH values. The immunoglobulin patterns of all five patients and of normal serum showed that IgG and IgM are eluted mainly with the MM and MB buffers, respectively, at both pH values, whereas IgA is eluted mainly with the MB buffer at pH 8, but at pH 7, shows a significant shift similar to that of macro-CK. These characteristic patterns allowed the identification of the immunoglobulin in macro-CK as IgA in the first four patients, and as IgM in the fifth patient.