Protein function, various effects

Mechanism of Action Acts as a coenzyme for various metabolic functions, including fat and carbohydrate metabolism and protein synthesis. Therapeutic Effect Necessary for cell growth and replication, hematopoiesis, and myelin synthesis. Pharmacokinetics In the presence of calcium, absorbed systemically in lower half of ileum. Initially, bound to intrinsicfactor this complex passes down intestine, binding to receptor sites on ileal mucosa. Protein binding High, Metabolized in the liver. Primarily eliminated unchanged in urine. Half-life 6 days. 

The p53 protein has various Ser/Thr phosphorylation sites. These include C-terminal phosphorylation sites for the CDKs of the S and G2/M phase. A controlling effect on DNA binding ability has been described for C-terminal phosphorylation so that a direct connection between the cell cycle machinery and the transcription-activating function of p53 seems possible via this route. 

Hemerythiin presents an excellent example of a protein where intermetallic effects are significant and well studied. Often elegant work using multiple techniques has revealed a great deal of information regarding the structure and function of the active site which contains two iron atoms. Various aspects of those studies have been reviewed by Klotz and co-workers47). 

Herrera, J.J., Pastroriza, L., and Sampedro, G. 2002. Effects of various cryostabihsers on protein functionality in frozen-stored minced blue whiting muscle The importance of inhibiting formaldehyde production. European Food Research and Technology 214 382-387. 

Thus it is quite evident that exogenous proteolytic enzymes alter the functionality of meat proteins, i.e. increase tenderness, by a more or less random attack on the various muscle proteins. However, this alteration occurs primarily during the cooking period because of denaturation of substrate proteins and the effects of increased temperature on enzyme activity. 

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