Clinical Enymes (Lecture | P) Flashcards
What are the characteristics of enzymes?
1) These are produced by living cells
2) These are proteins in nature
Enzymes are measured in terms of what?
These are measured in terms of their activity and not in terms of their absolute values
What are the factors that affect enzymatic rxns?
1) Enzyme concentration
2) Substrate concentration
3) Cofactors
a. Coenzymes
b. Activators
c. Metalloenzymes
4) Inhibitors
a. Competitive inhibitor
b. Non-competitive inhibitor
c. Uncompetitive inhibitor
What are the exs of coenzymes?
1) NADP
2) NAD
What are the exs of activators?
1) Ca
2) Mg
3) Zn
4) Cl
5) K
What are the exs of metalloenzymes?
1) Catalase
2) CO
What is the characteristic of competitive inhibitor (competitive inhibition)?
Reversible
What is the characteristic of non-competitive inhibitor (non-competitive inhibition)?
Irreversible
What is the principle of competitive inhibitor (or competitive inhibition)?
It binds to the active site of the enzyme
Substrate + inhibitor competes for the same active site
What is the remedy for competitive inhibitor (or competitive inhibition)?
Increase the concentration of substrate + serum dilution
What is the principle of non-competitive inhibitor (or non-competitive inhibition)?
The inhibitor binds at a place other than the active site
Substrate + inhibitor do not compete
What is the principle of uncompetitive inhibitor (uncompetitive inhibition)?
The inhibitor binds to the enzyme substrate (ES) complex
Increased ( / high) substrate = increased ( / high) inhibition
*What is the principle of rxn of Michaelis Menten Kinetics?
Enzyme + Substrate < – > ES complex -> Product + Free enzyme
What are the 2 enzymatic theories?
1) Emil Fisher’s ( / Fischer’s) Theory (Lock and Key)
2) Kochland’s Theory (Induced Fit)
What is the principle of Emil Fisher’s Theory?
The shape of the key (substrate) must conform into the lock (enzyme)
What is the principle of Kochland’s Theory (Induced Fit)?
Based on the attachment of a substrate to the active site of the enzyme
What are the 2 enzymatic rxns?
1) Zero Order reaction
2) First Order reaction
What are the 2 ways of expressing enzymatic activity?
1) International Unit (IU/U)
2) Katal Unit (KU)
What is International Unit?
It is the amt of enzyme that catalyzes 1 micromole of substrate/minute
What is Katal Unit?
It is the amt of enzyme that catalyzes 1 mole of substrate/second
1 IU is equal to how many nkat?
1 IU = 16.7 nkat
1 kat/L is equal to how many U/L?
1 kat/L = 0.06 U/L
What are the diff classification of enzymes?
1) Oxidoreductases
2) Transferases
3) Hydrolases
4) Lyases
5) Isomerases
6) Ligases
What is the meaning of ALP?
Alkaline phosphatase
What is the purpose of ALP?
Hepatic and bone marker
What are the diff isoenzymes of ALP?
1) Liver ALP
2) Bone ALP
3) Placental ALP
4) Intestinal ALP
What is the characteristic of bone ALP?
Heat labile
What is the characteristic of placental ALP?
Heat stable
What is the substrate for methods of ALP?
PNPP (P-nitrophenylphosphate)
What are the methods for ALP determination?
1) Bessy, Lowry and Brock
2) Bowers and Comb
What are the 2 types of carcinoplacental ALP?
1) Regan ALP
2) Nagao ALP
What is the characteristic of Regan ALP?
It is most heat stable
Regan ALP is most stable at what temp and at what time duration?
65 DC - 30 mins
What is the characteristic of Nagao ALP?
It is inhibited by L-leucine
Transaminases are significant in what?
These are significant in the evaluation of MI, hepatocellular disorders, and skeletal muscle disorders
What are the exs of transaminases?
1) SGOT
2) SGPT
Where is SGOT present?
1) Cardiac tissue
2) Liver
3) Skeletal muscle
4) Kidney - small amt
5) Pancreas - small amt
6) RBC - small amt
What is the other term for SGOT?
AST
What happens to AST lvls if a pt has AMI?
AST
1) Rises at 6 - 8 hrs
2) Peaks at 24 hrs
3) Normalize within 5 days
What is the sources of SGPT?
1) Liver - highest lvl
2) Kidney
3) Skeletal muscles
4) Cardiac tissue
5) Spleen
6) RBC - small amt