Applications and nitrogen metabolism

negative nitrogen balance

consumption<excretion

positive nitrogen balance

consumption>excretion

Kwashiorkor

• protein deficiency; adequate calories

• edema/swelling

Marasmus

• lack of all macronutrients/calories

• loose skin and muscle wasting

Creatinine

• waste product

• indicator of renal function

Selenocysteine

• no codon

• needs stop codon and Se to be present

Selenoproteins help these enzymes function:

thyronine iododases, glutamine peroxidases, and thioredoxin reductases

Porphyins are cofactors for ____ transport

O2

________ reacts with _____________ to yield ALA (aminolevulinate)

glycine; succinyl-CoA

Maple syrup disease (MSUD)

• improper breakdown of valine, leucine, and isoleucine

• breakdown leads to neurological damage

Homocystinuria is the build up of ______________

homocysteine

Homocystinuria is due to dysregulation of the

methionine cycle

treatment for Homocystinuria

B6 supplement (enzymes are PLP dependent; B6—> PLP)

Porphyria

• build-up of porphyrins

• can affect the skin or the nervous system

Degredation of iron-porphyrin/heme makes

bilirubin

Bilirubin accumulation can lead to

jaundice

PKU is the deficiency of

phenylalanine hydroxylase

PKU treatment

low phenyalanine diet and Tyrosine supplements

Orotic aciduria is caused by a deficiency of what enzymes

orotic phosphoribosyl transferase and orotidine-5-phosphate decarboxylase

Orotic aciduria may present as ______________ with normal B12

megaloblastic anemia

Orotic aciduria is defined by

increased orotic acid

Folic acid deficiency results in reduced _________ which leads to uracil being incorporated in DNA

thymidylate synthase

5-fluorouracil (5FU)

inhibitor of thymidylate synthase

(No dTMP)

Methotrexate

inhibitor of dihydrofolate reductase

(no H4 folate)

Lesch-Nyhan Syndrome

characterized by intellectural deficits/poor coordination

Lesch-Nyhan Syndrome is due to a lack of what enzyme

HGPRT (hypoxanthineguanine phosphoribosyltransferase)

Lesch-Nyhan Syndrome leads to an _____ purine salvage pathway

inactive

Gout

caused by excess uric acid in joints

Gout can be treated by

allopurinol

Allopurinol is an inhibitor of what enzyme

xanthine oxidase (xanthine —> uric acid)

Megaloblastic anemia

characterized by a B12 deficiency

Megaloblastic anemia replaces _______ with __________

erthyrocytes with macrocytes

Megaloblastic anemia treatment

B12