Protein body formation

GLUCONEOGENESIS FATTY ACID OXIDATION PROTEIN DEGRADATION KETONE BODY FORMATION... 

Two features of recombinant production in particular can impact very significantly upon the approach subsequently taken to purify the recombinant product inclusion body formation and the incorporation of purification tags. The processes of inclusion body formation, recovery and recombinant protein renaturation have been considered in Chapter 5. Once the recombinant protein has been refolded, additional purification (if required) follows traditional lines. 

What are the relationships of Lewy body formation, proteasomal protein degradation and mitochondrial dysfunction to parkinsonism (see ref. [8] for a detailed review). 

Chung, K. K., et al., Parkin ubiquitinates the alpha-synudein-interacting protein, synphdin-l implications for Lewy-body formation in Parkinson disease. Nat Med, 2001, 7(10), 1144-50. 

Figure 16.11 Pattern of fuel utilisation during prolonged starvation. The major metabolic change during this period is that the rates of ketone body formation and their utilisation by the brain increases, indicated by the increased thickness of lines and arrows. Since less glucose is required by the brain, gluconeogenesis from amino acids is reduced so that protein degradation in muscle is decreased. Note thin line compared to that in Figure 16.9.

In normal young children, the contribution of amino acid oxidation to energy requirement in starvation is about 1%, similar to that in the obese. In malnourished children, who have a protein-energy deficiency, it is even lower (4%). This suggests that a mechanism exists to protect muscle protein from degradation in children. Such a mechanism may involve a faster and greater increase in ketone body formation in children compared with adults (Chapter 7). 

The insoluble Ca(II) salts of weak acids, such as calcium phosphate, carbonate, and oxalate, serve as the hard structural material in bone, dentine, enamel, shells, etc. About 99% of the calcium found in the human body appears in mineral form in the bones and teeth. Calcium accounts for approximately 2% of body weight (18,19). The mineral in bones and teeth is mosdy hydroxyapatite [1306-06-5] having unit cell composition Ca10(PO4)6(OH)2. The mineralization process in bone follows prior protein matrix formation. A calcium pumping mechanism raises the concentrations of Ca(II) and phosphate within bone cells to the level of supersaturation. Granules of amorphous calcium phosphate precipitate and are released to the outside of the bone cell. There the amorphous calcium phosphate, which may make up as much as 30—40% of the mineral in adult bone, is recrystallized to crystallites of hydroxyapatite preferentially at bone collagen sites. These small crystallites do not exceed 10 nm in diameter (20). 

Chrunyk, B. A., Evans, J., Lillquist, J., Young, P., and Wetzel, R. (1993) Inclusion body formation and protein stability in sequence variants of interleukin-1 beta. J. 

To minimize ketosis, a slow but steady degradation of nonessential proteins would provide three-, four-, and five-carbon products essential to the formation of glucose by gluconeogene-sis. This would avoid the inhibition of the citric acid cycle that occurs when oxaloacetate is withdrawn from the cycle to be used for gluconeogenesis. The citric acid cycle could continue to degrade acetyl-CoA, rather than shunting it into ketone body formation. 

The accumulation of hydrogen peroxidase affects many intracellular processes and results in hemolysis. These include the cross-linking of membrane proteins hemoglobin denaturation (manifest as Heinz body formation), which in turn affects the physical properties of the erythrocyte and lipid peroxidation, which may affect the cell membrane to cause direct hemolysis (Fig. 11-8). The resultant damage leads to a mixture of intravascular hemolysis and extravascu-lar hemolysis (by which hemolysis occurs in the reticuloendothelial system). In acute hemolytic episodes, the clinical picture is of predominantly intravascular hemolysis, while predominantly extravascular hemolysis is seen in patients with chronic hemolysis. 

Mitra S, Tsvetkov AS, Kinkbeiner S (2009) Protein turnover and inclusion body formation. Autophagy 5 1037-1038... 

Georgiou, G. and Bowden, G.A. (1991). Inclusion body formation and the recovery of aggregated recombinant proteins. In Recombinant DNA Technology and Applications. A.Prokop, R.K.Bajpai, and C.Ho, eds. (New York McGraw-Hill), pp. 333 356. 

Chen Y, Song J, Sui SF, Wang DN. DnaK and Dual facilitated the folding process and reduced inclusion body formation of magnesium transporter CorA overexpressed in Escherichia coli. Protein Expr. Purif. 2003 32 221-231. 

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