P-Microglobulin

The three-dimensional structure of a large fragment of a human MHC class I protein, human leukocyte antigen A2 (HLA-A2), was solved in 1987 by Don Wiley and Pamela Bjorkman. Class I MHC proteins consist of a 44-kd a chain noncovalently bound to a 12-kd polypeptide called P " microglobulin. The a chain has three extracellular domains (a j,... 

Deconvolution of the ion series containing m/z 1067 revealed a molecular weight of 11,729 Da corresponding to the oxidized form of P-microglobulin that contains a single cysteine bridge. Characterization of the other components present in the mixture is currently in progress. 

Lactoperoxidase. Present in milk and saliva, LPO plays a role in the prevention of bacterial growth. In the compound I, the radical centre undergoes transferral from the porphyrin to the protein moiety. The resultant protein radical can react with other proteins. Thus, freeze-quench EPR has permitted the detection of protein radicals from P-microglobulin, casein and albumin. Radicals have also been observed following the activation of LPO in milk. ... 

Jones, E. M., and Surewicz, W. K. (2005). Fibril conformation as the basis of species- and strain-dependent seeding specificity of mammalian prion amyloids. Cell 121, 63-72. Kad, N. M., Myers, S. L., Smith, D. P., Smith, D. A., Radford, S. E., and Thomson, N. H. (2003). Hierarchical assembly of beta2-microglobulin amyloid in vitro revealed by atomic force microscopy./. Mol. Biol. 330, 785-797. 

B. Type II—Crass-[5 Spine Models GNNQQNY and P 2-Microglobulin... 

Monti, M., Principe, S., Giorgetti, S., Mangione, P., Merlini, G., Clark, A., Bellotti, V., Amoresano, A., and Pucci, P. (2002). Topological investigation of amyloid fibrils obtained from beta2-microglobulin. Protein Sci. 11, 2362-2369. 

The structure of MHC. In the context of antigen recognition by T cells, we are primarily concerned with class I and II MHC molecules. Class III MHC are essentially a part of the complement system. Class I molecules are made up of transmembrane heavy-chain peptide, which is noncovalently associated with the B2 microglobulin (B2m) molecule. Class II, on the other hand, is composed of two smaller transmembrane peptide chains, a and p. The peptides are arranged in domains that are of comparable size to those of the immunoglobulin molecules. 

The concentrations of phosphate and glucose were measured on all samples and the urine samples were subject to detailed protein analysis two small proteins, retinol binding globulin and P-2-microglobulin (P2M), received particular attention. Unfortunately, none of the markers alone or in combination proved to be entirely appropriate, but a rising concentration of P2M was able to identify nearly three-quarters of subjects who subsequently showed some degree of renal damage. 

Class I MHC proteins occur in almost all nucleated cells. They mainly interact with cytotoxic T cells and are the reason for the rejection of transplanted organs. Class 1 MHC proteins are heterodimers (a 3). The p subunit is also known as P2-microglobulin. 

Defects in MHC Class II molecules, while exposing affected subjects to a variety of infections, do not result in the severe immunodeficiency seen in patients with SCID. In contrast to mutations affecting MHC Class II molecules, defects in MHC Class I molecules are rare. Mutations affecting MHC Class I molecules are directed to genes on chromosome 6 at the MHC locus that code for peptide-transporter proteins (122). The function of these transporter proteins is to transport the peptide antigens so that a complex with the a chain of MHC Class I molecules and p 2-microglobulin is formed and transported to the surface of the cell. 

Chaussidon M, Netter P, Kessler M, et al. 1993. Dialysis-associated arthropathy Secondary ion mass spectrometry evidence of aluminum silicate in beta2-microglobulin amyloid synovial tissue and articular cartilage. Nephron 65 559-563. 

Junghans, R P. and Anderson, C. L. (1996). The protection receptor for IgG catabolism is the b2-microglobulin-containing neonatal intestinal transport receptor. Proc. Natl. Acad. Sci. USA 93 5512-5516. 

P5. Pezzilli, R., Billi, P., Miniero, R., Fiocchi, M., Cappelletti, O., Morselli-Labate, A. M., Barakat, B., Sprovieri, G., and Miglioli, M., Serum interleukin 6, interleukin 8, and beta-2 microglobulin in early assessment of severity of acute pancreatitis. Comparison with serum C-reactive protein. Dig. Dis. Sci. 40, 2341-2348 (1995). 

Studies of renal function in stainless steel welders, whose exposure is mainly to chromium(VI) compounds, were negative. Stainless steel welders had significantly increased (p<0.001) levels of urinary chromium, increased clearance of chromium, and increased serum creatinine compared with controls, but no differences were found in the levels of retinol binding protein, p2-microglobulin or other indices of kidney damage (Verschoor et al. 1988). Similar negative results were found in another group of stainless steel welders (Littorin et al. 1984). 

Occupational exposure to chromium(III) or chromium(O) does not appear to be associated with renal effects. No renal impairment based on urinary albumin, retinol binding protein, and renal tubular antigens was found in 236 workers employed in the ferrochromium production industry where ferrochromite is reduced with coke, bauxite, and quartzite. The mean airborne concentration of chromium in various sample locations was 0.075 mg chromium(III)/m3 chromium(VI) was below the detection limit of 0.001 mg chromium(VI)/m3 at all locations (Foa et al. 1988). Workers employed in an alloy steel plant with a mean exposure of 7 years to metallic chromium at 0.61 mg chromium(0)/m3 and to other metals had normal urinary levels of total protein and p2-microglobulin, enzyme activities of alanine-aminopeptidase, N-acetyl-P-D-glucosaminidase, gammaglutamyl-transpeptidase, and P-galactosi-dase (Triebig et al. 1987). In boilermakers exposed to chromium(O), no increase in urinary levels of... 

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