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
What is the characteristic of SGPT?
It is a specific test
What is the cofactor for SGPT?
Pyridoxal phosphate
What is the other term for pyridoxal phosphate?
Vitamin B6
What are the methods for determination of SGPT lvls?
1) Reitman and Frankel
2) Karmen
What is the meaning of ACP?
Acid phosphatase
What are the fxns of ACP?
1) It can be used for the detection of prostatic CA
2) It can be used in forensic chem
What are the sources of ACP?
1) Prostate
2) RBC
3) PLTs
4) Bone
5) Spleen
6) Kidneys
What are the methods for ACP?
1) Roy
2) Hillman
*What is utilized in Roy and Hillman procedures for determination of ACP lvls?
Thymolphthalein monoPO4 ( / phosphate?)
What happens in ACP lvls in room temp?
It decreases within 1 - 2 hrs
What is the stabilizer added for determination of ACP lvls (w/c is present in room temp)?
Citric acid
What are the characteristics of prostatic ACP?
1) Specific ACP
2) Inhibited by L-tartrate
What are the characteristics of red cell / non prostatic ACP?
1) Non-specific ACP
2) Inhibited by HCHO (formaldehyde) & cupric ions
What is the fxn of amylase?
It catalyzes the breakdown of starch
What is the organ affected whenever there are alterations in amylase lvls of the pt?
Pancreas
What is the meaning of AMS?
Amylase
What are the isoenzymes of AMS?
1) Salivary AMS
2) Pancreatic AMS
What is the characteristic of salivary AMS?
It is anodal
What is the characteristic of pancreatic AMS?
It is cathodal
What are the characteristics of AMS?
1) It is the smallest enzyme in terms of size
2) Since it is the smallest enzyme in terms of size, it can be readily filtered by the glomerulus resulting for it to appear in the urine
What is the size of AMS?
50,000 MW
What happens to AMS lvls if the pt has acute pancreatitis?
1) Initial rise: 2 - 12 hrs after onset of an attack (earliest marker)
2) Peak lvl: 24 hrs
3) Normal lvl: 3 - 5 days
*What is the principle of the method done by AMS?
From substrate to starch
*What are the methods for determination of AMS lvls?
1) Saccharogenic
2) Amyloclastic
3) Chronometric
What is the fxn of lipase?
It is an enzyme that catalyzes the ester linkages of fats to produce alcohol and FA (formic acid? / folic acid?)
What is the organ affected if there are alteration to the lipase lvls of the pt?
Pancreas
What is the meaning of LPS?
Lipase
What is the purpose of LPS?
It serves as a sp marker for acute pancreatitis
What is the characteristic of LPS?
It is not affected by renal disorder
What happens to the LPS lvls if the pt has acute pancreatitis?
1) Initial rise: 6 hrs after onset of attack
2) Peak: 24 hrs
3) Elevated: 7 days (late pancreatic marker)
What is the method for determination of LPS lvls?
Cherry Crandall
What is the substrate used in Cherry Crandall for the determination of LPS lvls?
50% olive oil or triolein
What are the fxns of lactic dehydrogenase?
It is useful in monitoring:
1) Myocardial
2) Hematological
3) Hepatic disorders
What is the characteristic of lactate dehydrogenase?
It lacks specificity due to various organ sources
What are the types of lactic dehydrogenase?
1) LD1
2) LD2
3) LD3
4) LD4
5) LD5
Where are LD1 & LD2 present?
1) Heart muscles
2) RBC
3) Renal cortex
Where are LD3 present?
1) Lungs
2) Spleen
3) Pancreas
4) WBC (lymphocytes)
Where are LD4 & LD5 present?
1) Liver
2) Skeletal muscles
3) Ileum
4) Skin
What is the relationship bet LD2 and LD1 physiologically?
Physiologically, LD2 > LD1
What is the condition present in flipped pattern?
Instead of LD2 > LD1, it is LD1 > LD2
When do flipped pattern happen?
In cases of:
1) MI
2) Hemolytic anemia
3) Renal infarction
At what conditions are lactate dehydrogenase elevated the highest?
1) Pernicious anemia
2) Hemolytic disorders
What is the meaning of LD?
Lactate dehydrogenase
*What is the other type of LD?
LD-6 (LD6)
*Where is LD-6 present?
Alcohol dehydrogenase (arteriosclerotic failure)
What are the methods for the determination of LD lvls?
1) Wacker method
2) Wrobleuski La Due
What is the characteristic of Wacker method?
It is forward and employs direct rxn
What is the characteristic of Wrobleuski La Due?
It is reverse and it employs indirect rxn
What is the meaning of CPK?
Creatinine phosphokinase
*What are the fxns of CPK?
1) It detects damage to myocardial and skeletal muscles
2) It can be utilized for dx of AMI and Duchenne disorder (CK-MM)
What happens to the lvl of CPK if the pt has Duchenne disorder?
CK (creatinine kinase) is elevated the highest
*What are the diff types of CPK?
1) CPK 1 or BB
2) CPK 2 or MB
3) CPK 3 or MM
Where can CPK 1 be found?
1) Brain
2) Lungs
3) Prostate
4) Kidney
5) Thyroid
6) Uterus
7) Intestine
Where can CPK 2 be found?
1) Heart muscles
2) Tongue
3) Esophagus
Where can CPK 3 be found?
1) Heart
2) Skeletal muscles
*What are the characteristics of NTR?
1) CK-BB rarely seen in serum of adults (high molecular size)
2) Sudden appearance in serum suggests myocardial release = CK-MB > or equal to 6% of the total CPK (indicates AMI)
3) Liver cells and RBC do not contain CK
What is the major isoenzyme in the normal sera?
CK-MM
What is the percentage of CK-MM in the normal sera?
94 - 100%
What are the methods used for the determination of CPK lvls?
1) Tanzer-Gilbarg
2) Rosalki and Hess
What are the characteristics of Tanzer-Gilbarg method?
1) It is forward
2) It employs direct rxn
What are the characteristics of Rosalki and Hess?
1) It is reverse
2) It employs indirect rxn
