Calcium proteins

The meat diet resulted in markedly greater titratable acid and calcium excretion compared with the soy diet (P<0.02). This occurred despite the fact that each diet contained the same amounts of protein, calcium, phosphorus, and sulfur. Increased urinary calcium excretion in subjects accompanied this increased output of TTA (P<0.02) ... 

None of these earlier animal studies had been rigorously for protein, calcium, or acid output. The data of the present study demonstrated that the acid nature of the diet, fed at constant levels, and to the same subjects, induced hypercalciuria in the meat period. 

In a study by Mueller and Cooney (21) rats fed a diet containing 0.45% calcium and 16% cocoa powder showecf a lower growth rate and body calcium than those on a control diet. However, oxalic acid did not account for the total decrease in body calcium. Rats 25-27 days old were pair-fed the basal ration for 5 weeks. The only variable in the ration was cocoa. The decreased growth rate occurred in the cocoa-fed rats in spite of the fact that they received more calories, protein, calcium and phosphorus than controls. 

Effect of Dietary Protein, Calcium, and Phosphorus on Calcium Metabolism in Humans... 

Calcium effects. The biochemical effects of Ca "" in the cytoplasm are mediated by special Ca -binding proteins calcium sensors"). These include the annexins, calmodulin, and troponin C in muscle (see p. 334). Calmodulin is a relatively small protein (17 kDa) that occurs in all animal cells. Binding of four Ca "" ions (light blue) converts it into a regulatory element. Via a dramatic conformational change (cf 2a and 2b), Ca -calmodulin enters into interaction with other proteins and modulates their properties. Using this mechanism, Ca "" ions regulate the activity of enzymes, ion pumps, and components of the cytoskeleton. 

A. Azzi B. Chance (1969) Biochim. Biophys. Acta 189, 141. Selected entries from Methods in Enzymology [vol, page(s)] Calibration of calcium binding, 260, 425-427 luminescence measurement, 260, 424-425 mitochondria-targeted hybrid protein [calcium quantitation, 260, 418, 422, 424-428 stable expression, 260, 418-421 transient expression, 260, 420 intracellular localization, 260, 421-425 reconstitution with coelenterazine, 260, 422-422] structure, 260, 418. 

SlOO proteins, calcium binding, 46 451-456 Spruhtrocken process, 4 26 Square-planar complexes, 4 157-164 octahedral, compared, 4 162-174 in solution, 34 270-271 Square-planar iridium complexes, 44 295, 297 Square-planar nickel macrocyclic complexes equilibrium with octahedral species, 44 116-118... 

Dalgliesh, I), G. and Parker, T. G. 1980. Binding of calcium ions to bovine asi-casein and precipitability of protein-calcium ion complexes. J. Dairy Res. 47, 113-122. 

Nutrients frequently consumed in sub-optimal concentrations by humans are proteins, calcium, non, vitamin A, thiamin (vitamin Bl), riboflavin (vitamin B2) and ascorbic acid (vitamin C). Some of these nutrients occur in higher concentrations in fruit juices than hi other foods. There is experimental evidence that indicates that ascorbic acid of natural origin is apparently superior to that of synthetic origin. 

Barbeau, W. E. and Hilu, K. W. (1993). Protein, calcium, iron and amino acid content of selected wild and domesticated cultivars of finger millet. Plant Foods Hum. Nutr. 43,97-104. 

Protein, calcium, vitamins A and D needed to prevent the loss of bone minerals that frequently occurs with increasing age... 

Nonbacterial milk components and components produced from milk fermentation may also contribute to the immunostimulatory activity of yogurt. Peptides and free fatty acids generated by fermentation have been shown to enhance the immune response. Milk components such as whey protein, calcium, and certain vitamin and trace elements also can influence the immune system. 

Wilson-Ashworth HA, Judd AM, Law RM, Freestone BD, Taylor S et al. (2004) Formation of transient non-protein calcium pores by lysophospholipids in S49 lymphoma cells. J Membr Biol 200 25-33... 

Petrov Al, Volodkin DV, Sukhorukov GB (2005) Protein-calcium carbonate co-precipitation. A tool for protein encapsulation. Biotechnol Prog 21 918-925... 

Thrombin (MW 39,000) is a proteolytic enzyme of the serine protease group. It is derived from prothrombin, a circulating plasma protein, through the proteolytic action of a complex consisting of the proteolytic enzyme factor X (or factor Xa), another protein called factor V (accelerator protein), calcium, and phospholipid. Factor V has recently been identified as the plasma copper protein ceruloplasmin or a similar protein (see Chapter 6). 

One of the characteristics of protein calcium channels is their sensitivity to ablock by transition metal cations. Lanthanum is a particularly potent blocker. It is suggested that permeant and blocking ions compete for the common binding sites in the channels. The PolyP-PHB channel complexes are also blocked by transition metal cations in a concentration-dependent manner. A nearly complete block of single-channel currents was observed in the synthetic complexes at concentations > 0.1 mM La3+ (0.1 % of Ca2+) (Das et al., 1997). Evidently, PHB-PolyP complexes are versatile ion carriers whose selectivities may be modulated by small adjustments of the local pH. The results may be relevant to the physiological function of PHB-PolyP channels in bacteria and the role of PHBs and PolyPs in the Streptomyces lividans potassium channel (Das and Reusch, 2001). 

The complexity of food effects on zinc absorption is illustrated by the studies of Sandstrom et al.(25,37,38) in which phytate, protein, calcium, zinc and other factors appear to have variable effects on zinc absorption. Although It appears certain that food interferes with zinc absorption, the effects of individual food substances are unknown and difficult to predict. Regardless of individual effects, zinc administration with food will complicate efforts to measure the effects of other variables on intestinal absorption. 

Different from trigger proteins, parvalbumin and calbindinD9k frmction as calcium-buffer proteins. Calcium binding to both proteins does not lead to conformational change with an exposed hydrophobic surface. The structure of a carp parvalbumin was the first structure in the EF-hand protein family. It has two isoforms (a and fi) with very similar stmctures. Oncomodulin is the mammahan beta hnkage parvalbumin. The stmcture of parvalbumin comprises three helix-loop-helix motifs, called AB, CD, and EF initially (Figure 11). The calcium-binding loop in the first... 

Fig. 12. Protein in the presence of 0.5% lanthanum chloride slightly depresses atomic absorption of calcium — — — 0.1% protein — —g— 0.4% protein —A—A— 0.8% protein. Calcium concentrations of samples actually aspirated were only one tenth of those given on the abscissa (from reference (Z3) by permission).

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