Flashcards in Biochem metabolism Deck (129)
ATP is carrier molecule for what
NADH, NADPH, FADH2 is carrier molecule for what
Coenzyme A, lipoamide is carrier molecule for what
Biotin is carrier molecule for what
THF is carrier molecule for what
1 carbon units
SAM is carrier molecule for what
TPP is carrier molecule for what
What processes is NADPH used in? why?
anabolic processes (steroid & FA synthesis) to reduce equivalents;
What is NADPH a product of?
what are the universal electron acceptors?
Nicotinamides (NAD+ from vitB3 & NADP+) & flavin nucleotides (FAD+ from vit B2);
What processes is NAD+ used in?
Catabolic processes to carry reducing equivalents away as NADH
Describe the 1st step in glycolysis & 1st step of glycogen synthesis in the liver. what is the result?
phosphorylation of glucose to G-6-P via hexokinase or glucokinase
traps glucose inside the cell
Describe where, speed and what leads to use of hexokinase
ubiquitous w/ high affinity (low Km), low capacity (low Vmax)
UNINDUCED by insulin
inhibited by G-6-P
Describe where, speed and what leads to use of glucokinase
Liver & Beta cells of pancreas use GLUT-2 which has low affinity (high Km), high capacity (high Vmax)
INDUCED by insulin
High Vmax bc it cannot be satisfied
Describe how glucose is sequestered dependent on its concentration
At low glucose (low insulin) then hexokinase sequesters glucose into the tissue;
At high glucose, excess glucose is stored in the liver
Where does glycolysis occur?
Since RBC's use glycolysis only, What will occur if the MC enzyme deficiency is present?
Pyruvate kinase deficiency will decrease pyruvate along w/ leading to hemolytic anemia due to the cell swelling & increased bilirubin
Gluconeogenesis & Glycolysis are regulated by what?
F-2,6-BisP & PFK-2
The pyruvate DH complex contains 3 enzymes that require 5 cofactors - name them
1) pyrophosphate (B1, thiamine (TPP))
2) FAD (B2, riboflavin)
3) NAD (B3, niacin)
4) CoA (B5, pantothenate)
5) Lipoic acid
Other than the fed state, what else activates the pyruvate DH complex? what is the result?
exercise leads to
increased NAD+/NADH ratio
What 2 complexes use the same cofactors w/ similar substrate & action?
Pyruvate DH complex to make Acetyl-CoA & alpha-KG DH complex in TCA cycle to make succinyl-CoA
What poison will damage the pyruvate DH & alpha-KG DH complexes? what is the result?
Arsenic inhibits lipoid acid leading to vomit, rice water stools, garlic breath
If you have a muscle Bx that reveals increased glycogen, increased F-6-P & decreased pyruvate, what is the cause?
deficiency in PFK-1
What are the enzymes responsible for increased & decreased levels of F-2,6-BP?
Describe how a SANS response will change F-2,6-BP in the liver & muscle
Liver levels will decrease thus decreasing glycolysis
Muscle levels will increase to activate PFK-1 to increase glycolysis
Pyruvate DH complex deficiency will lead to a backup of what? result?
pyruvate & alanine resulting in lactic acidosis
What are most cases of Pyruvate DH complex deficiency due to? What are the findings?
XL gene for E1-alpha subunit of PDC causing neuro defects that typically start in infancy
Acquired Pyruvate DH complex deficiency can come from what?
Decreased in B vitamins especially thiamine
What is the Tx for Pyruvate DH complex deficiency?
increase intake of ketogenic nutrients such as HIGH FAT content or increased lysine (dairy, fish) & leucine (eggs, soy)