Lecture 2 (Protein & AA metabolism)

Question 1

What are some major nitrogen containing compounds?

Answer 1

Amino acids, proteins, purines/pyrimidines, neurotransmitters, creatine phosphate, haem, some hormones (adrenaline)

Question 2

What are the uses of creatine?

Answer 2

Breakdown of creatine and creatine phosphate is creatinine. It is produced at a constant rate dependent on muscle mass of a person. Creatinine can be collected in urine providing an estimate of muscle mass.

Used as an indicator as damage to the kidneys: raised plasma level and low urine level of creatinine.

Question 3

How much creatinine is excreted per day for men/women?

Answer 3

Men: 14-26 mg/kg
Women: 11-20 mg/kg

Question 4

What is N equilibrium (normal state)?

Answer 4

Intake of protein is the same as the output.
Output is from loss of skin/hair/nails, majority being from N-waste products in faeces and urine
NO CHANGE TO TOTAL BODY PROTEIN.

Question 5

What is positive N balance?

Answer 5

Intake of nitrogen exceeds output.
Seen in rapid growth and pregnant women, or an adult recovering from malnutrition.
INCREASE IN TOTAL BODY PROTEIN (this is normal)

Question 6

What is negative N balance?

Answer 6

Intake of protein is less than the output. This is dangerous.
Causes: trauma, infection, malnutrition

Question 7

What happens when you have more protein than you need?

Answer 7

Metabolise the protein. Liver removes amino group (-NH2) leaving a carbon skeleton. Convert amino groups