Most of serum proteins are synthesized by the liver, which decreased in its concentration in response to partial hepatectomy and this may be due to reduction in liver mass, the production of liver protein is mainly directed to the regenerating process than the production of the exported serum proteins. Serum proteins have a dynamic existence with degradation and synthesis continuously replacing the protein circulating at any time , the rate of synthesis equals the rate of degradation, so the concentration Of protein in serum remain s constant, so that the tendency for concentration of serum, proteins to remain constant implies, the existence of a mechanism determining the rate of production, the rate of degradation or both . In case of proteins whose serum level fall (ceruloplasmin, ¿-l-antitrypsin, prealbumin, B-lipoprotein, ¿-1-macroglobulin, ¿-1-acidglycoprotein, cholinesterase and haemopexin) particularly those with small molecular size as albumin, transferrin are accompanied by an increase in degradation of albumin or increase in catabolism must exceed increase in the synthesis . The changes in rates of degradation of individual proteins do not parallel with the changes in rat

Hanan Farouk Aly AbduallahProf.biochemistry ,Therapeutic Chemistry Dep., National Research Centre,Egypt .