Phosphate proteins

Ca2+-sensing Receptor Calpains Protein Phosphates S100 Proteins... 

Moreover, several buffer systems exist in the body, such as proteins, phosphates, and bicarbonates. Proteins are the most important buffers in the body. Protein molecules contain multiple acidic and basic groups that make protein solution a buffer that covers a wide pH range. Phosphate buffers (HPO T /H2P07) are mainly intracellular. The pK of this system is 6.8 so that it is moderately efficient at a physiological pH of 7.4. The concentration of phosphate is low in the extracellular fluid but the phosphate buffer system is an important urinary buffer. Bicarbonate (H2C03/HC0 3) is also involved in pH control but it is not an important buffer system because normal blood pH 7.4 is too far from its pK 6.1 [144],... 

The earliest compensatory response is to chemically buffer excess bicarbonate by releasing hydrogen ions from intracellular proteins, phosphates, and hemoglobin. If respiratory alkalosis is prolonged (more than 6 hours), the kidneys attempt to further compensate by increasing bicarbonate elimination. 

Example 30 Bialy and Waldman in their synthesis of protein phosphates 2A inhibitor (4S, 5S, 6S, lOS, US, 12S) cytostatin have found that application of the fluorenylmethyl protecting group (Fm) allowed successful formation of the phosphate moiety [62]. Initial experiments with the methoxybenzyl group, successfully employed in the synthesis of fostriecin [63] failed. The 2-cyanoethyl protecting group was also not suitable because that one 2-cya-noethyl group could be removed without destroying the whole molecule (Examples 25 and 26). 

Due to these functions, the protein phosphatases are an indispensable part of signal transduction processes involving protein phosphorylation. It is therefore not surprising that the protein phosphates are subject to diverse and complex regulation. 

Regulation of acetyl-CoA carboxylase by phosphorylation and dephosphorylation. Glucagon is known to activate cAMP-dependent protein kinase this kinase phosphorylates both serine 77 and serine 1200 of rat acetyl-CoA carboxylase, which inactivates the enzyme. However, there is also an AMP-dependent kinase that phosphorylates serine 79 and serine 1200 and inactivates the rat acetyl-CoA carboxylase. The relative importance of these two kinases in regulating the carboxylase in vivo is still unclear. Likewise, the phosphorylated enzyme is a substrate for several different protein phosphate phosphatases, and the physiologically relevant phosphatases are not known. Epinephrine may inhibit the carboxylase via a Ca2+-dependent protein kinase. 

Immunotype Neutral Sugars Amino Sugars Lipid A KD0 Protein Phosphate... 

Keywords Tetrafluoroaluminate, Fluoroaluminates, Aluminates, G-proteins, Phosphate... 

Phosphoproteins. An important group that includes many major food proteins. Phosphate groups are linked to the hydroxyl groups of serine and threonine. This group includes casein of milk and the phosphoproteins of egg yolk. 

Buffers. The normal tear pH of 7.5 depends on bicarbonates and, to a lesser degree, proteins, phosphates. 

E.C. Bate-Smith, The buffering of muscle in rigor protein, phosphate and carnosine. J. Physiol, 92 (1938)336-343. 

Starch Amyiose (%) Amyiopectin (%) Lipid (%) Protein (%) Phosphate (%)... 

Protein + Phosphate —— Chetator ol Calcium Free Calcium (Ca ) Bound Calcium... 

Dilution with lanthanum-HCl reduces interference from protein, phosphate, citrate, sulfate, and other anions. Phosphate causes the greatest interference because calcium-phosphate complexes are not dissociated readily by the air-acetylene flame. Lanthanum-HCl dissociates complexes, ensuring that all fractions of calcium (free, protein-bound, and complexed) are measured. Dilution effectively reduces the viscosity, which can also interfere by reducing the aspiration rate and atomization of the specimen. 

Many physiological anions, including protein, phosphate, citrate, lactate, sulfate, and oxalate, form complexes with calcium ions. Although these anions reduce the concentration of free calcium by complex formation, they do not directly interfere with the measurement of the calcium that is free. Protein deposits on the electrode may act as a divalent cation exchanger, resulting in positive interference with high concentrations of Mg. Older electrodes were sensitive to the concentration of protein in the sample. The newer electrodes use a dialysis membrane or neutral carrier to reduce or eliminate this protein effect. Investiga-... 

In acid environments proteins may form protein-phosphate complexes of low solubility. The metaphosphates, which are less hydrated than the ortophosphates, form complexes that are less soluble than those with ortophosphates. This has been utilized for the modification of functional properties of protein concentrates and preparations, for separation of proteins in different food processing operations, and in treatment of protein-containing food plant effluents. 

The initial response of the body to acute respiratory alkalosis is chemical buffering. Hydrogen ions are released from the body s buffers— intracellular proteins, phosphates, and hemoglobin—and titrates down the serum bicarbonate concentration. This process occurs within minutes. Acutely, the bicarbonate concentration can be decreased by a maximum of 3 mEq/L for each 10-mm Hg decrease in PaC02 (see Table 5IM). When only the physicochemical buffering has occurred, the disturbance is referred to as acute respiratory alkalosis. 

The carbonic acid dissociates, releasing hydrogen ions, which are buffered by nonbicarbonate buffers (i.e., proteins, phosphate, and hemoglobin) and bicarbonate. Thus on the basis of physicochemical factors, increases in PaC02 raise the serum bicarbonate concentration. In general, in acute respiratory acidosis, the bicarbonate concentration increases by 1 mEq/L above 24 for each 10-mm Hg increase in PaC02 above 40 (see Table 51 ). 

The original authors later replied (L. W. Tremblay, G. Zhang, J. Dai, D. Dunaway-Mariano and K. N. Allen, J. Am. Chem. Soc. 2005, 127, 5298) by analysing the protein/phosphate ratios of the crystals, but using imperfect and potentially non-specific colour tests. 

Spinelli et al. (14) determined the emulsion stability and emulsion capacity of polypeptides recovered from hydrolysates of fish myofibrillar protein using hexametaphosphate. In general the emulsion capacity and emulsion stability increased through 30 min of proteolysis but then declined. Even the unhydrolyzed protein-phosphate complex yielded better emulsion stability and capacity values compared with sodium caseinate. The effect of the residual hexametaphosphate in the hydrolysate conceivably could have a beneficial effect on emulsifying characteristics of the modified fish myofibrillar proteins. 

S Colloidiil inorganic phosphate, 38.5% n] Protein phosphate (casein), 20% ... 

Sephadex gels Exclusion Serum proteins Phosphate buffers UV absorbance ... 

Dor6e, M., T. Lorca A. Picard. 1991. Involvement of protein phosphatases in the control of cdc2 kinase activity during entry into and exit from M-phase of the cell cycle. Adv. Protein Phosphat. 6 19-34. 

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