ENZYMES Flashcards
1
Q
Higher the enzyme concentration, the faster is the reaction, because more enzyme is present to bind with substrate
A
Enzyme Concentration
2
Q
The reaction rate steadily increases as more subtrate is added
A
Substrate concentration
3
Q
Organic Compound
Increasing its concentration will increase the velocity of an enzymatic reaction
Essential to achieve absolute enzymatic activity
Ex: NAD & NADH
A
Coenzymes
4
Q
Inorganic ions which alters the spatial configuration of enzyme for proper substrate binding
Ex: Calcium, Zinc, Chloride, Magnesium & Potassium
A
Activators
5
Q
Inorganic ion attached to a molecule
Ex: Catalase & Cytochrome Oxidase
A
Metalloenzymes
6
Q
Physically binds to the active site of an enzyme
Inhibition is reversible when the substrate concentration is significantly higher than concentration of inhibitor
A
Competitive Inhibitor
7
Q
Does not compete with substrate but look for areas other than the active sire
Subtrate & Inhibitor may bind an enzyme simultaneously
A
Non-Competitive Inhibitor
8
Q
Inhibitor binds to the enzyme-substrate (ES) complex
Increasing substrate concentration results to increase inhibition
A
Uncompetitive Inhibitor
9
Q
Enzymes having the same catalytic reactions but slightly different molecular structures because of differences in the amino acid sequence of enzymes
A
Isoenzymes
10
Q
Enzymes are active at what temperature?
A
25C
30C
37C (Optimum)
11
Q
Most physiologic reactions occur in the pH range of ___
A
7 to 8
12
Q
Ideal temperature for preservation of enzymes
A
-20C
13
Q
Ideal storage temperature for substrates and coenzymes
A
2 - 8C
14
Q
Ideal for storage of LDH
LDH4
LDH5
Cold labile LDH
A
22C or Room temperature
15
Q
Catalyze the removal or addition of electrons
Ex:
1. CO
2. LDH
3. MDH
4. ICD
5. G-6-PD
A
Oxidoreductases
16
Q
Catalyze the transfer of a chemical group other than hydrogen form one substrate to another
Ex:
1. CK
2. AST
3. ALT
4. OCT
A
Transferases
17
Q
Catalyze hydrolysis or splitting of a bond by the addition of water
Ex:
1. ACP, ALP, CHS, LPS
2. Trypsin, Pepsin, LAP
3. AMS, Galactosidases
A
Hydrolases
18
Q
Catalaze removal of groups from substrates without hydrolysis
Ex:
1. Glutamate decarboxylase
2. Pyruvate decarboxylase
3. Tryptophan decarboxylase
4. Aldolase
A
Lyases
19
Q
Catalyze the intramolecular arrangement of the substrate-compound
Ex:
1. Glucose phosphate isomerase
2. Ribose phosphate isomerase
A
Isomerases
20
Q
Catalyze the joining of two substrate molecules, coupled with breaking of pyrophosphate bond in ATP or similar compound
Ex:
1. Synthase
A
Ligases
21
Q
Reaction rate depends only on enzyme concentration
A
Zero-order reaction
22
Q
Reaction rate is directly proportional to substrate concentration
A
First-Order reaction
23
Q
Hig Specificity Enzymes:
A
Acid Phosphatase
Alanine Aminotransferase
Amylase
Lipase
24
Q
Principal tissues of High Specificity enzymes:
A
- ACP - RBC & Phosphate
- ALT - Liver
- Amylase - Pancreas, Salivary gland
- Lipase - Pancreas
25
Moderate Specificity Enzymes:
1. Aspartate Aminotransferase
2. Creatinine Kinase
26
Principal tissues of Moderate Specific Enzymes
1. AST - Liver, Heart, Skeletal Muscles
2. CK - Brain, Heart, Skeletal Muscles
27
Low Specificity Enzymes
1. Alkaline Phosphate
2. Lactate Dehydrogenase
28
Principal tissues of Low Specific Enzymes:
1. ALP - Liver, Bone, Kidney
2. LDH - All tissues
29
Nonspecific enzyme capable of reacting with many different substrates
Liberates inorganic phosphate from an organic phosphate ester with concominant production of an alcohol
Alkaline Phosphate
30
Major Isoenzymes of ALP
1. Liver ALP
2. Bone ALP
3. Placental ALP
4. Intestinal ALP
31
Reference Value of ALP:
30 - 90 U/L
32
ALP is higher in individuals of blood group ___ because of differences in intestinal ALP levels
Group B & O
33
Inc. ALP is the Major liver fraction that is most frequently elevated especially in what disease___
Obstructive Jaundice
34
For bone disorders, highest elevations of ALP occurs in what disease?
Paget's Disease
Osteitis deformans
35
Found in lung, breast, ovarian and gynecological cancers
Bone ALP co-migrator
**Most heast stable ALP (65C for 30 mins)**
Inhibited by Phenylalanine reagent
| Carcinoplacental ALP
Regan ALP
36
Found in adenocarcinoma of pancreas and bile duct, pleural cancer
Inhibited by L-leucine and phenylalanine
Nagao ALP
37
Most anodal isoenzyme:
Liver ALP
Bone ALP
38
Least Anodal ALP
Intestinal ALP
39
Performed at 56C for 10-15 minutes
Heat Fractionability/ Stability Test
40
Most heat Stable Isoenzyme:
Placental ALP
41
Most Heat Labile ALP
Bone ALP
42
Decreasing order of ALP heat stability
Placental, Intestinal, Liver, Bone
43
This method uses different concentrations of phenylalanine, synthetic urea and levamisole solutions
Chemical Inhibition Test
44
L-phenylalanine inhibits what isoenzyme of ALP?
Placental
Intestinal
45
3M Urea inhibits what isoenzyme of ALP
Bone ALP
46
Levimasole reagent inhibitis what ALP
Liver ALP
Bone ALP
47
Reference Method & Most Specific method in determining ALP levels:
Bowers & McComb
(Szasz Modification)
48
Substrate of the Bowers & McComb method:
p-nitrophenylphosphate
49
End product of Bowers & McComb Method:
p-nitrophenol or
Yellow nitrophenoxide ion
50
What is a component ALP?
What is its enzyme activator?
1. Zinc
2. Magnesium
51
Decreased ALP is seen in what deficiency:
Zinc deficiency
52
Useful tumor marker in serum and CSF for most germ cell tumors
Placental Alkaline Phosphatase (PLAP)
53
1. Osteitis deformans
2. Obstructive jaundice
3. Osteomalacia
4. Rickets
5. Osteoblastic bone tumors
6. Sprue
7. Hyperparathyroidism
8. Hepatitis and Cirrhosis
Increased ALP
54
Catalyzes the same reaction made by ALP, except that it is active at pH **5.0**
Levels >50 IU/L indicates presence of seminal fluid in the sampe:
Acid Phosphatase
55
Tissue sources of ACP
1. Prostate (Major source)
2. RBCs
3. Platelets
4. Liver
5. Bone
56
Reference Value of ACP:
Male: 2.5-11.7 U/L (Total ACP)
57
ACP is used for the detection of what cancer:
Prostatic Adenocarcinoma
58
Seminal-fluid ACP activity can persists for up to how many days?
4 days
59
What is the specific substrate used and the substrate of choice for quantitative endpoint reaction for ACP
Thymolphthalein monnophosphate
60
Substrate preferred for continuous monitoring methods:
a-naphthly PO4
61
If not assayed immediately, serum should be frozen or acidified to a pH lower than __
6.5
62
1. Prostatic Carcinoma
2. Breast, Lung, Thyroid Carcinoma
3. Gaucher's Disease
4. Niemann Pick Disease
Increased ACP
63
More sensitive than Prostatic Acid Phosphatase in detecting stages A & B prostatic cancer:
Prostate-Specific Antigen
64
Involved in the transfer of an amino group between aspartate and a-ketoacids with the formation of **Oxaloacetate & Glutamate**
Aspartate Aminotransferase
65
Other name of AST:
Serum Glutamic Oxaloacetic Transaminase
66
In AMI, AST levels:
1. Rise
2. Peak
3. Normalize
1. 6-8 hours
2. 24 hours
3. 5 days
67
Uses Malate Dehydrogenase and monitors the change in absorbance at 340 nm
Substrare: Oxaloacetate & Glutamate
Karmen Method
pH 7.5
68
Catalyzes the transfer of an amino group from alanine to a-ketoglutarate with the formation of **Glutamate & Pyruvate**
Highest concentration in Liver
**More Liver-Specific than AST**
Alanine Aminotransferase
69
Other name of ALT
Serum Glutamate-Pyruvate Transaminase
70
ALT measurement is a more sensitive and specific screening test for ____ compared to AST
Posttransfusion Hepatitis or
Occupational Toxic Exposure
71
Aminotransferases requires ___ as coenzymes
Pyridoxal Phosphate or
Vitamin B6
72
Hemolysis should be avoided because it increases AST by:
10 times
73
Method used for ALT:
Coupled Enzymatic Reaction
pH 7.5
74
De Ritis Ratio
AST/ALT
75
In children De Ritis ratio:
AST>ALT
76
In adults, De Ritis Ratio:
ALT > AST
77
De Ritis Ratio of:
1. < 1
2. > 1
3. 1-2
4. > 2
1. Viral Hepatitis
2. Nonviral origin Hepatic disease
3. Hepatic Cirrhosis
4. Alcoholism: Hepatocellular Carcinoma
78
Catalyzes the breakdown of starch and glycogen
An important enzyme in the physiologic digestion of starch
Smallest enzyme in size
**Earliest pancreatic marker**
Amylase
79
In AP, AMS levels:
1. Rise
2. Peak
3. Normalize
1. 2-12 hours
2. 24 hours
3. 3-5 days
80
Classic reference method expressed in Somogyi units
Measures the amount of reducing sugars produced by the hydrolysis of starch by the usual glucose method
Saccharogenic
81
Measures amylase activity by following the decreases in substrate concentration
Amyloclastic
82
Measures amylase activity by the increase in color intensity of the soluble dye-substrate solution
Chromogenic
83
Measures amylase activity by a continuous-monitoring technique
Coupled-Enzyme Method
84
Enzymes used for the Coupled-Enzyme fmethod for AMS:
1. Amylase
2. Glucosidase
3. Hexokinase
4. G-6-PD
85
Normal Amylase/Creatinine Ratio:
1%-4%
0.01 - 0.04
86
A:C Ratio in Acute Pancreatitis
(>) 4%
up to 15%
87
A/C Ratio Formula:
(Urine AMS/Serum AMS) x (Serum crea/Urine Crea) x 100
88
Enzyme that hydrolyzes the ester linkages of fats to produce alcohol and fatty acid
Catalyzes partial hydrolysis of dietary TAG in the intestine to the 2-monoglyceride intermediate
**Most specific pancreatic marker**
Lipase
89
In AP, LPS levels:
1. Rise
2. Peak
3. Remains Elevated
4. Normalize
1. 6 hours
2. 24 hours
3. 7 days
4. 8-14 days
90
In this disease, there are cell degradation that occurs and results into loss of amylase and lipase production
Chronic Pancreatitis
91
**Uses Olive Oil as substrate**
Lipase Methods
92
Hydrolysis of olive oil after incubation for 24 hours at 37C and titration of Fatty acids using NaOH
Substrate: 50% Olive Oik
End: Fatty Acid
Cherry Crandal Method
**Reference Method
93
Most commonly used method
Does not use 50% Olive Oil
Peroxidase Coupling
94
Enzyme that cataluzes the conversion of lactic and pyruvic acid
Zinc-containing enxymr that is part of glycolytic pathway
Has 5 Isoenzymes
Lactate Dehydrogenase
95
Tissue Sources:
1. Heart, RBCs, Kidneys - LD1 & LD2
2. Lungs Pacnreas, Spleen - LD3
3. Skeletal Muscles, Liver, Intestine - LD4 & LD5
96
Highest LD levels are seen in what disease?
Pernicious anemia
Hemolytic Disorders
97
In AMI, LD levels:
1. Rise
2. Peak
3. Elevated
1. 12-24 hours
2. 48-72 hours
3. 10-14 days
98
Hepatic Carcinoma & Toxic hepatitis will have __ increase
ten-fold
99
In normal sera, LD pattern:
LD2 - LD1 - LD3- LD4 - LD5
100
Flipped pattern (LD1>LD2) is seen in what diseasse?
Myocardial Infarction &
Hemolytic Anemia
101
Reaction is at pH 8.8
Most commonly used method because it produces a positive rate and not affected by product inhibition
Wacker Method
Forward Method
102
Reaction at pH 7.2
2x faster as the forward reaction
preferred method for dry slide tech
Wrobleuski La Due
Reverse method
103
Cold-labile LD isoenzyme:
LD5
104
Catalyzes the transfer of a phosphate group between creatine phosphate and adenosine diphosphate
Storage of High-energy creatine PO4 in the muscles
Creatine Kinase
105
Most anodal, and Most labile CK isoenzyme
CK1
106
Least Anodal CK
CK 3
107
CK is a very sensitive indicator of what diseases?
Acute Myocardial Infarction &
Duchenne Diorder
108
Highest elevation of total CK is seen in?
Duchenne's Muscular Dystrophy
(50x)
109
In AMI, CK levels:
1. Rise
2. Peak
3. Normalize
1. 4-8 hours
2. 12-24 hours
3. 48-72 hours
110
Done at pH 9.0
Forward reaction
Measures Creatine
Enzymes: CPK, PK, LD
Tanzer-Gilbarg Assay
111
Most commonly used method
Faster reaction
pH 5.8
Reverse method
Measures Creatine Phosphate
EnzymeS: CPK, HK, G6PD
Oliver Rosalki Method
112
Percentage of total CK that is attributed to CK-MB
CK Relative Index (CKI)
113
Formula for CKI
(CK-MB/Total CK) x 100
114
Glycolytic enzyme that splits Fructose-1,6-diphosphate into two triose phosphate molecules in the metabolism of glucose
Aldolase
115
Isoenzymes of Aldolase:
1. Aldolase A - Skeletal muscles
2. Aldolase B - WBC, Liver, Kidney
3. Aldolase C - Brain Tissue
116
Phosphoric monoester hydrolase
Predominantly secreted from the liver
**Marker for HEPATOBILIARY DISEASE & INFILTRATIVE LESIONS OF THE LIVER
5' Nucleotidase
117
Catalyzes the transfer of glutamyl groups between peptides or amino acids through linkage as a gamma carboxyl group
Gamma Glutamyl Transaminase
118
Useful in differentiating source of an increased ALP level
Elevated in all hepatobiliary disorders - biliary tract obstructions
**Most sensitive marker for Acute Acoholic Hepatitis**
Sensitive indicator of alcoholism
Gamma Glutamyl Transamine
119
Secreted by liver, and reflects the Synthetic function of liver rather than hepatocyte injury
Catalyzes removal of benzyl group from cocaine
**Marker for Insecticide/Pesticide poisoning**
Pseudocholinesterase
120
Also known as Peptidyldipeptidase A or Kininase II
Converts Angiotensin 1 to Angiotensin 2 within lungs
**Critical target for inhibitory drugs designed to lower blood pressure**
Angiotensin-Converting Enzyme
121
Also a marker for hepatobiliary diseases:
Ornithine Carbamoyl Transferase (OCT)
122
Functions to maintain NADPH in the reduced form in the erythrocytes
Newborn screening marker
Deficiency can lead to drug-induced hemolytic anemia after taking primaquine (anti-malarial drug)
Glucose-6-Phosphate Dehydrogenase
