• relationship between dietary uptake of nitrogenous compounds and loss of nitrogenous compounds
• normal: intake = loss

• creatinine
• bilirubin
• uric acid
• ammonia
• urea

• intake is less than loss
• results in catabolism of body proteins
• if not corrected, leads to death

• growth
• pregnancy and lactation
• recovery from surgery
• recovery from illness

• Leu
• Ile
• Val
• Met
• Thr
• Lys
• Phe
• Trp

Cant make aromatic ring, cant do the branching

• compare to casein (in milk) and ovalbumin (in egg white)
• high quality- mix of all the AA we need and in the right proportions
• low quality- low conc. of one or more of the essential AA's
  • ex: collagen- has nothing but Gly and hydroxy-Pro
  • ex- plant proteins

Name the non-essential AA's

• Ser
• Ala
• Glu
• Asp
• Gly
• Gln
• Asn
• Pro

Trp

• increase demand to catabolize proteins
• this leads to breakdown of negative nitrogen balance

Effect of overbundance of protein and total callories

Kwashiorkor

Nutritional Marasmus

ammonia

urea

creatinine

uric acid

• synthesis/breakdown of tissue protein
• synthesis of important nitrogenous compounds and their degredation
• metabolism of individual AA's

TISSUE PROTEIN does not contribut much to this AA pool

AA precursor for heme and its breakdown product?

• N source for heme is Gly
• the breakdown product is bilirubin

AA that is the precursor to creatine. Breakdown product?

• use Gly (one N) and Arg (2 N's)
• breakdown product is creatinine

• N sources is Gln, Asp
• no breakdown product (reusable)

• N source is Gly, Gln, Asp
• breakdown products
  • uric acid (excrete in urine)
  • ammonia (also made from other sources like deamination of AA's)
  • urea (synthesized in liver as end product of ammonia detox)

Process of AA breakdown

• deaminate to produce alpha keto acid
• breakdown alpha keto acid into glucose and acetyl-CoA

Examples of ketogenic AA's

• Lys
• Leu

• Ile
• Phe
• Tyr
• Trp

Some C's go to glucose while others go to acetyl CoA.

transamination

deamination

• takes a donor alpha amino acid and an acceptor alpha keto glutaric AA
• donor AA binds to pyridoxal phosphate in aminotransferase
• acceptor alpha keto glutaric acid comes in and picks up the amino group to form Glu

FREELY REVERSIBLE (if I need to make/remove it, YES I CAN!!!!)

Ala aminotransferase (ALT)

Asp aminotransferase (AST)

Enzyme responsible for deamination of Glu

acts as a oxidase to D and L AA's

• via serine/threonine dehydrogenase
• use water (take away for intermediates than add it back to teh fainal product)
• NON reversible

• via serine dehydrognase
• involves using H2S
• NON reversible

Cys

Ser

Thr

Glu

• vitamins- start with pyridoxOL and make pyridoxAL (the aldehyde form)
• coezyme- when phosphate adds to pyridoxal

• ALT- cytosol
• AST- mitochondria

These enzymes work together to form keto acid and glutamate, respectively.