Protein

Protein has many functions in our body, for example it is used as apoprotein, maintain the fluid and electrolyte balance, as buffers, immunity response, provides energy, growth and as hormones. Excessive intake of protein will induce fluid imbalance since more water is needed, liver disturbances and shorter life span due to toxicity by products. Besides that, excessive intake of protein will make our body loss calcium. The breakdown of protein to sulfur containing amino acids causes the urine becoming more acidic, forcing it to carry out more calcium with the excess protein. Several disorder related to protein are homocystinuria and phenylketonuria. Homocystinuria is due to lack of cystathionine synthhetase where accumulation of methionine and homocysteine cause atherosclerosis. Phenylketonuria is disease lacking of phenylalaline hydroxylase where accumulation of phenylalaline damage brain and mental retardation.

There are some terminology for protein, such as protein efficiency ration, biological value and net protein utilization. Protein efficiency ration is defined as a measure of protein quality assessed by determines how well a given protein to support weight gain in laboratory animals. Biological value is the measure of the nitrogen retained in the body divided by the amount of the nitrogen absorbed from protein. Net protein utilization is the ratio of amino acid converted into protein compared to the ratio of amino acid supplied.