Development of an amino acid sequence-dependent analytical method for peptides using near-infrared spectroscopy.

We aimed to develop an amino acid sequence-dependent analytical method using near-infrared (NIR) spectroscopy. The detailed analysis of the NIR spectra of eight different amino acid aqueous solutions (glycine, alanine, serine, glutamine, lysine, phenylalanine, tyrosine, and proline) revealed different spectral patterns characteristic of different amino acid residues in the 6200-5700 and 5000-4200 cm-1 regions, and the amino acids were identified based on the patterns. The spectra in the region of 5000-4500 cm-1 for tripeptide organic solutions that were composed of the aforementioned eight amino acids clearly showed the spectral differences depending on the amino acid species and amino acid sequences. Namely, tripeptide species were clearly differentiated from each other based on the spectral pattern of NIR bands due to the combinations of N-H stretching and amide II/III modes and those derived from the first overtones of amide II and amide I. The quantitative evaluation of changes in the concentrations of dipeptides and tripeptides composed of two different amino acids, glycine and proline was performed using partial least squares regression (PLSR) analysis and a combination of bands for amide modes. The calibration and validation results with high determination coefficients (R2 ≥ 0.99) were successfully obtained based on the amino acid sequences. The results not only revealed the usefulness of NIR spectroscopy as a process analytical technology (PAT) tool for synthesizing peptides in a micro flow reactor but also proposed a general method for quantitatively analyzing NIR spectra obtained in the course of chemical synthesis.

[A case of renal Fanconi syndrome due to Bence Jones' protein K-type multiple myeloma].

A 60-year-old man, who had been treated for chronic kidney disease and chronic hepatitis B infection, was referred to our hospital following presentation with thoracic bone pain and exacerbation of proteinuria and hematu- ria. On admission, laboratory test results showed evidence of hypophosphatemia, glucosuria and elevated levels of both urinary NAG and 62MG.The patient was diagnosed with Fanconi syndrome based on findings indicating the presence of pan-aminoaciduria, elevated urinary excretion of uric acid and an increased phosphorus reabsorption rate. Furthermore, bone scintigraphy showed increased multiple symmetric uptake of radiotracer in both sides of the ribs, leading to the diagnosis"of hypoposphatemia-related osteomalacia with renal Fanconi syndrome. Urinary immunoelectrophoresis indicated the presence of K Bence Jones' protein (BJP). A bone marrow biopsy examina- tion showed that the plasma-to-cell ratio was less than 10%. However, the patient had over lg/day of proteinuria and suppression of serum IgM (18mg/dL) and was, therefore, diagnosed with multiple myeloma based on SWOG criteria. Light microscopic examination showed evidence of glomerulosclerosis, intimal thickness of interlobular arteries and acidophilic granular deposits in the cytoplasm of the proximal epithelial tubular cells. Immunofluores- cence indicated positive anti-K staining in these regions. Electron microscopic examination of the proximal tubular epithelial cells revealed the presence of numerous diamond-shaped and oval crystals, thought to be the K light chain of BJP. In general, cast nephropathy, light chain deposition disease (LCDD) and AL amyloidosis are recog- nized renal injuries caused by myeloma. However, there have been few clinical reports of Fanconi syndrome with multiple myeloma, such as the case study we have described here. In addition, histological examination of a biopsy sample provided further evidence of K BJP in the proximal epithelial tubular cells.