Mayumi Imoto

Capillary zone electrophoresis of albumin‐depleted human serum using a linear polyacrylamide‐coated capillary: Separation of serum α‐and β‐globulins into individual components

The separation of human serum globulins into individual components was investigated by capillary zone electrophoresis (CZE) using a linear polyacrylamide‐coated capillary at pH 7.4. Prior to CZE analysis of globulin components present in serum, it was found that it was necessary to remove albumin. Preparation of albumin‐depleted human serum with a HiTrap Blue column allowed the detection of α‐ and β‐globulin components as a series of peaks. Almost all the peaks, both narrow and broad, observed in CZE analysis could be assigned to six globulin components (α1‐acid‐glycoprotein, α1‐antitrypsin, haptoglobin, α2‐macroglobulin, Gc‐globulin, and transferrin) by using the technique of antibody‐based indirect detection. The CZE results, obtained from serum preparations from three healthy adults and six patients, showed that the CZE system might be capable of detecting qualitative differences among individuals with regard to individual globulin components.

Occurrence of heavy chain of 7S IgM half-molecule whose NH2-terminal sequence is identical with that of κ light chain sequence in patients with Waldenstrom macroglobulinemia

We report a rare case of a half molecule 7S IgM (HM 7SIgM) consisting of a unique mu heavy chain and kappa light chain found in blood and urine samples from a patient with primary Waldenstrom macroglobulinemia. A 64kDa abnormal immunoglobulin was detected in serum and urine by immunoblot method, and purified by a two-dimensional SDS-PAGE after separation from IgG and albumin fractions on gel filtration. NH2-terminal amino acid sequence analysis of the heavy chain revealed that residues 1-20 were identical to those of the NH2-terminal region of kappa light chain derived from the same patient. This sequence was then followed by a sequence that could not be identified by a computer homology search on the protein database. Using polypeptide segments obtained from the unique mu chain by digestion with endopeptidase, we identified a sequence spanning from residue 127 in the variable region of the known mu chain to residue 19 in the known CH1 domain and a sequence spanning from residues 67-82 in the heavy chain variable region class II. From these results, we concluded that the 64 kDa protein was an abnormal half molecule 7S IgM consisting of a kappa light chain and a unique mu heavy chain of 35 kDa polypeptide in which the NH2-terminal 20 amino acids were replaced by 20 amino acids derived from the sequence of kappa light chain in the NH2-terminal region.

A Case of Waldenstrom Macroglobulinemia with Temporary Appearance of 7S IgM Half Molecule

BACKGROUND We encountered a rare case of Waldenstrom macroglobulinemia with temporary appearance of 7S IgM half molecule and with monoclonal proteins binding to agarose gel. METHODS The patients serum and urine were analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The N-terminal amino acid sequences of the IgM with abnormal mass (68 kDa) were determined and compared with those of known immunoglobulin. RESULTS The 68 kDa IgM consisted of a defective μ chain (36 kDa) and an intact κ chain. N-terminal amino acid sequence analysis demonstrated that the defective μ chain had the variable region of IgM. The agarose gel-binding ability of the IgM-κ M-protein was lost after reduction or alkaline treatment of serum. CONCLUSIONS The 7S half molecule IgM in the present case may miss a large part of the constant region of the µ chain.

A new type of temperature-dependent serum M protein: a case of IgG-λ type multiple myeloma

Abstract Background: We report a rare case of temperature-dependent serum M protein (thermoprotein), monoclonal IgG1-λ protein isolated from 90-year-old female with advanced multiple myeloma. Methods: M protein was identified in the blood plasma of the patient by immunoelectrophoresis (IEP). To evaluate the types of bonds, the properties of the protein after reduction and chemical treatment were examined. Results: This protein was irreversibly precipitated at or above room temperature when exposed in the air. This protein was redissolved by 30 mmol/l dithiothreitol, 4 mol/l urea, or 8 mmol/l EDTA. Conclusions: Unlike other immunoglobulins reported to date, this data suggests that hydrogen, disulfide, and ionic bonds are involved in the temperature-dependent precipitation of this M protein.