PROTEIN SENSITIVITY

Synthesis of the transferrin receptor (TfR) and that of ferritin are reciprocally linked to cellular iron content. Specific untranslated sequences of the mRNAs for both proteins (named iron response elements) interact with a cytosolic protein sensitive to variations in levels of cellular iron (iron-responsive element-binding protein). When iron levels are high, cells use stored ferritin mRNA to synthesize ferritin, and the TfR mRNA is degraded. In contrast, when iron levels are low, the TfR mRNA is stabilized and increased synthesis of receptors occurs, while ferritin mRNA is apparently stored in an inactive form. This is an important example of control of expression of proteins at the translational level. 

Volkova KD, Kovalska VB, Tatarets AL, Patsenker LD, Kryvorotenko DV, Yarmoluk SM (2007) Spectroscopic study of squaraines as protein-sensitive fluorescent dyes. Dyes Pigm... 

Hamann CP Natural rubber latex protein sensitivity in review. Am J Contact Derm 4 4, 1993... 

Bravo R, Cells JE. (1982) Human proteins sensitive to neoplastic transformation in cultured epithelial and fibroblast cells. Clin Chem 28, 949-54. 

Fluorescence-activated cell sorter (FACS) To predict and select cells in the population that express target protein Sensitive and allows direct sorting and cloning of positive cells Required proteins expressed intracellnlarly or on the cell snrface. Not sensitive for expression system engineered to secrete the protein... 

In addition to analyzing a protein for characteristics dictated by its specific nature, routine analytical assays are performed namely, amino acid analyses and amino- and carboxy-terminal sequencing. If necessary, disulfide assignments are made. A search is ordinarily conducted for oxidations and/or deamidations. In the case of recombinant proteins particular attention is paid to detecting signal sequences or proteolytically degraded species. In contrast, deletions and chemical modifications can be a consequence of proteins prepared by chemical synthesis. Lastly, tests are applied to determine if the protein is correctly folded into its native three dimensional structure. In addition, with recombinant proteins, sensitive immunological procedures are performed to ensure that host cell proteins have not been copurified with the protein of interest. 

Journot L, Homburger V, Pantaloni C, Priam M, Bockaert J, Enjalbert A (1987) An islet activating protein-sensitive G protein is involved in dopamine inhibition of angiotensin and thyrotropin-releasing hormone-stimulated inositol phosphate production in anterior pituitary cells. J Biol Chem 363 15106-15110. 

Lactose intolerance is a distinct entity from cow milk protein sensitivity and causes abdominal pain, diarrhea, nausea, flatulence, and/or bloating. While avoidance of milk and other dairy products will bring relief in children suffering from lactose intolerance, it may cause problems in optimal bone mineralization owing to lack of calcium in diet. Several lactose-free and lactose-reduced milks are now available in markets to cater to such infants. The scope of transgenic technology to reduce the lactose content in the milk of small animals has been reviewed elsewhere in this chapter (Section IV.A). The extension of this technique to include farm animals is targeted in the future. 

Endo, Y., Lee, M.A., and Kopf, G.S. (1988). Characterization of an islet-activating protein sensitive site in mouse sperm that is involved in the zona pellucida-induced acrosome reaction. Dev. Biol. 729 12-24. 

Seeley, E.H. et al., Enhancement of protein sensitivity for MALDI imaging mass spectrometry after chemical treatment of tissue sections, J. Am. Soc. Mass Spectrom., 19(8), 1069, 2008. 

Su F, Schneider RJ (1997) Hepatitis B virus HBx protein sensitizes cells to apoptotic killing by tumor necrosis factor alpha. Proc Natl Acad Sci USA 94 8744-8749 Sun DY, Jiang S, Zheng L, Ojcius DM, Young JD (1994) Separate metabolic pathways leading to DNA fragmentation and apoptotic chromatin condensation. J Exp Med 179 559-568... 

The patient s serum or urine sample and a Normal Human Serum Control are electrophoresed on the agarose plate. Antisera then are added to troughs in the plate and allowed to diffuse into the agarose support medium. When a favorable antigen-to-antibody ratio exists, a precipitin arc will form on the plate. Diffusion is halted by rinsing the plate in 0.85 % saline. Unbound protein is washed from the plate by the saline, and the antigen/antibody precipitin arcs are stained with a protein-sensitive stain. The precipitin arcs formed by the patient s sample and the control are compared for a semiquantitative protein analysis. 

What is not often appreciated is the extent to which immune responses to soybean proteins influence the growth and development in both humans and livestock. Three to eight percent of children develop immune responses to soybean proteins, sensitivities that usually result in gastrointestinal disturbances that are outgrown upon reaching puberty. Nonetheless, as much as 2% of adults present with a lasting sensitivity to soybean products (see refs. 7, 8 for review). 

Itagaki M, Komori S, Unno T, Syuto B, OhashiH (1995) Possible involvement of a small G-protein sensitive to exoenzyme C3 of Clostridium botulinum in the regulation of myofilament Ca -sensitivity in p-escin skinned smooth muscle of guinea pig ileum. Jap J Pharmacol 67 1-7... 

Other possibiHties include Ot blockers (36) and calcium antagonists (37). Other unproven agents include the P-adrenoreceptor agonists, phosphodiesterase inhibitors that affect movement of sodium and potassium through cellular channels, and calcium contractile protein sensitizers (38). Any of these agents and the appropriate cellular mechanisms that prevent or slow morphologic alteration in the heart or blood vessels should counteract the aging process. 

Kim Y, Suh N, Sporn M, Reed JC. An inducible pathway for degradation of FLIP protein sensitizes tumor cells to TRAIL-induced apoptosis. J Biol Chem 2002 277 22320-22329. 

---