 In animals , amino acids are obtained through the consumption of foods containing protein . Ingested proteins are then broken down into amino acids through digestion , which typically involves denaturation of the protein through exposure to acid and hydrolysis by enzymes called proteases . Some ingested amino acids are used for protein biosynthesis , while others are converted to glucose through gluconeogenesis , or fed into the citric acid cycle . This use of protein as a fuel is particularly important under starvation conditions as it allows the body 's own proteins to be used to support life , particularly those found in muscle . Amino acids are also an important dietary source of nitrogen . 
 In animals , amino acids are obtained through the consumption of foods containing protein . Ingested proteins are then broken down into amino acids through digestion , which typically <a href='uninflect' title='1'><mark>involves</mark></a> denaturation of the protein through exposure to acid and hydrolysis by enzymes called proteases . Some ingested amino acids are used for protein biosynthesis , while others are converted to glucose through gluconeogenesis , or fed into the citric acid cycle . This use of protein as a fuel <a href='drop_aux' title='2'><mark>is</mark></a>particularly important under starvation conditions as it <a href='uninflect' title='3'><mark>allows</mark></a> the body <a href='null_genetive' title='4'><mark>'s</mark></a>own proteins to be used to support life , particularly those found in muscle . Amino acids <a href='drop_aux' title='5'><mark>are</mark></a>also an important dietary source of nitrogen . 
In animals , amino acids r obtained through the consumption of foods containing protein . Ingested proteins are then broken dwn into amino acids thru digestion , which typically involve denaturation of da protein through exposure to acid and hydrolysis by enzymes called proteases . Some ingested amino acids are used for protein biosynthesis , while others arronverted to glucose through gluconeogenesis , or fed into the citric acid cycle . This use of protein as a fuel particularly important under starvation conditions as it allow tdabody  own proteins to be used to support life , particularly those found in muscle . Amino acids also an important dietary source of nitrogen .