Catabolism Of Amino Acid

introduction

you mean studied the fate of nitrogen, released as ammonia from different amino acids in unit 2 of the block. of protein which constitute the chief structural and functional element of the living system. About half of the body protein (predominately collagen)is present in the supportive tissue (skeleton and connective),while other half is intracellular.

all protein are continuously synthesized and degraded at different rates their degradation release amino acids amino acid come from the digestive of dietary protein. an adult human being has approx. 100g of free amino acids which represent an amino acid pool; out that glutamine and glutamine collectively make up about 50%while essential amino acids constitute about 10% of the amino acid pool. the concentration of intracellular amino acids is always higher than that of extracellular amino acids.

 

in this unit you shall learn about the catabolism of the carbon skeleton of amino acids by grouping them into families based on common product(s) formed after partial degradation. 

overview of amino acid metabolism

the cellular protein undergo continuous turnover to release amino acids and then reutilize a large part of them (70% to 80%) for synthesis of new protein and other nitrogen containing biomolecules (nucleotide,  hemi ,neurotransmitters ,each day ,human turnover 1-2 % of the total body protein ,principally muscle protein .it is a reflection of the balance between protein synthesis and protein degradation .individual protein undergo degradation at different rates and these rates can change in response to various signals.

generally structural protein have a longer half -life while most enzyme and regulatory /enzyme have half lives ranging from minutes to hours. 

amino acids catabolism yields intermediates which serves a variety of roles such as energy provision ;synthesis of glucose ,fatty acid and ketone bodies or simply to replenish TCA cycle intermediates. the synthesis of carbohydrate and fatty acids becomes the predominant fate when protein intake exceeds our requirements. the consumption of excess amino acids (derived from dietary protein )serves no longer term purpose as excess amino acids are are not stored but degraded. the major site of amino acid degradation in mammals as fuels primarily in muscle ,adipose tissue ,kidney and brain the muscle generates >50% of the  body pool of free amino acids.