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114 Cards in this Set
- Front
- Back
Enzymes |
Protein catalysts produced by living cells |
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Enzymes are produced by? |
All living cells |
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Enzymes do what to chemical reactions? |
Speed up |
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Catalyst |
Any chemical that speeds up a reaction |
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Substrate is |
The reactant/chemical the enzyme is going to act upon |
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Major influence on enzyme reactions |
Substrate concentration |
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Michaelis and Menten hypothesized the role of substrate concentration in formation of |
Enzyme substrate complex |
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Substrate readily binds to free enzyme at |
A low substrate concentration |
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When the amount of enzyme exceeds the amount of substrate, the reaction |
Steadily increases as more substrate is added |
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Stereo-enzymes |
work on only one steoisomer but not the other steoisomer |
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Stereo-enzymes |
work on only one stereoisomer but not the other stereoisomer |
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Enzymes cause what with reactions? |
Causes reactions to proceed at a much faster rate by lowering the energy of activation |
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Active site/binding site |
areas of the enzyme where the substrate attaches and where the reaction takes place |
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Substrate must fit into sites... |
exactly |
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Lock and key theory for substrates |
Lock - Enzyme Key- Substrate |
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Apoenzyme (protein) + cofactor (non-protein helper) ----------------> |
Holoenzyme |
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activator |
inorganic ions Ca2+ Mg2+ Zn2+ Cl-1 Minerals (charged ions) |
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Coenzyme |
Organic compount, vitamin B family, riboflavin is B2 |
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Coenzyme |
Organic compound, vitamin B family, riboflavin is B2 |
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activator = |
some enzymes need metal/nonmetal ions for the enzyme to work |
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Coenzyme- what is necessary for certain enzymes to work? |
Organic molecules |
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Examples of coenzymes |
NAD, NADP (loosely bound to enzyme) |
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Prosthetic group |
Organic portion that is tightly bound to the apoenzyme or protein portion |
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Proenzyme |
the inactive precursor of the enzyme. |
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Example of proenzyme |
Pepsinogen is precursor to pepsin |
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Another example of proenzyme |
clotting factors |
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Proenzymes are for |
protection |
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Isoenzymes |
different forms of the same enzyme, unique to certain organs |
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Isoenzymes |
different forms of the same enzyme, unique to certain organs |
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Examples of Isoenzymes |
LDH, ALP, CPK, ACP |
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Isoenzymes can be separated by |
heat sensitivity, chemical inhibition, immunassay, chromtaography |
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What does Immunassays use |
antibodies and electrophoresis |
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CK or CPK is rich in |
heart muscle and skeletal muscle |
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Isoenzyme structure of CK (Creatine kinase) or CPK (C Phosoho kinase) : CK1 |
CK1 = BB |
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Isoenzyme structure of CK (Creatine kinase) or CPK (C Phosoho kinase) : CK2 |
CK2 = MB |
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Isoenzyme structure of CK (Creatine kinase) or CPK (C Phosoho kinase) : CK3 |
CK3 = MM |
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CK2 can be found in |
the heart |
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CK3 can be found in |
Skeletal muscle |
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LD isoenzymes : LD1 |
LD1 = HHHH |
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LD isoenzymes : LD2 |
LD2 = HHHM |
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LD isoenzymes: LD3 |
LD3 = HHMM |
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LD isoenzymes: LD4 |
LD4 = HMMM |
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LD isoenzymes: LD5 |
LD5 = MMMM |
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Enzymes that transfer hydrogens, oxygen, or electrons from one molecule to another molecule |
Oxidoreductase |
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Group of atoms from one molecule to another molecule (dehydrogenase) LD (Lactate dehydrogenase) |
Transferase |
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Digestive enzymes from one to another |
Hydrolase |
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Enzyme that breaks down molecules w/o using water |
Lyase |
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Enzyme that changes L forms of a molecule to a D form |
Isomerase |
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Ligase |
Enzyme that joins 2 molecules and forms one molecule |
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ALP pH |
9.8 or 10 |
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ALP pH |
9.8 or 10 |
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GAMMA GTP or GAMMA GT OR GGTP |
Gamma glutamyl Transpeptidase |
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GGTP comes from |
The liver and hepatobiliary system |
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No GGTP comes from |
Human heart muscle or skeletal muscle |
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GGTP is specific for |
Iiver |
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GGTP more sensitive to what disorders in liver |
Cholestasis and obstructive jaundice |
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GGTP is VERY SENSITIVE TO |
Alcohol abuse - used to monitor alcholism |
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ALP ( BONE ENZYME) |
Alkaline phosphatase |
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Alkaline phosphatase found in BLIP |
Bone, liver, intestine, placenta |
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Optimum reaction pH for alkaline phosphatase |
9.7 or 9.8 or 10 |
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Alkaline phosphatase is found mainly in |
Bone and liver |
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Alkaline phosphatase is higher in |
Children because of its important part in bone formation |
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Alkaline phosphatase is increased in what bone disease |
Paget's disease and rickets |
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Alkaline phosphatase is also increased in |
Liver disease |
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Preferred substrate for measuring alkaline phosphatase |
P nitrophenol phosphate |
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Alkaline phosphatase is stable for how many hours at room temperature? |
8 hours |
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Alkaline phosphatase is stable for how long frozen? |
1 week at 4 degrees Celsius;one month Frozen |
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Heat differential test for Alp of bone liver and placental origin |
Liver is stable at 56 degrees, bone is labile at 56 degrees, placenta is stable at 65 degrees |
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Muscle enzymes |
CK, AST, and aldolase |
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Aldolase is only found in |
Muscle |
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Pancreatic enzymes include |
Amylase and lipase |
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Which pancreatic enzyme is more specific and which is sensitive? |
Amylase is more sensitive and lipase is more specific |
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Function of amylase |
Hydrolyzes starches (polysaccharides) into small molecules maltose and glucose |
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Amylase is important in the digestion of |
Carbohydrates |
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Amylase is present in |
Salivary glands and pancreas |
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Serum concentration of amylase will be what an acute pancreatitis |
Increased |
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Why would a physician become interested in amylase? |
Because pancreatitis does not involve a need for operation |
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What factors can affect the measurement of amylase |
Anticoagulants that bind calcium, chloride ions, must use saline. Fluoride, avoid gray top tubes, saliva |
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How long is amylase stable |
For a week at room temperature |
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What is the optimum pH for amylase? |
7.0 |
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Alpha amylase prefers the 1.4 linkages ______ not _____ (1.6 linkages) |
Amylose not amylopectin |
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Methods of measuring amylase: Saccharoogenic method |
Involves measurement of reducing sugars hydrolyzed from polysaccharides. Most accurate |
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Amyloclastic method |
Measures the change in the physical property of starch. Starch is the substrate and measures the staining property (using iodine) rate of disappearance measured by reaction with starch (blue color) rate of disappearance is proportional to amylase concentration |
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Kinetic method (starch) |
Involves 4 to 5 reactions using NAD+NADH |
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Amylase is the only plasma enzyme that is found in the |
Urine |
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Amylase has a low molecular weight that can be cleared by the |
Kidney |
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Amylase can remain elevated in the urine for |
7 to 10 days |
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In serum, amylase is elevated for |
2-3 days |
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Lipase |
Unique enzyme that works on the surface area of fats |
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Lipase ONLY comes from |
Pancreas |
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Lipase parellels amylase but.... |
Remains elevated longer in acute pancreatitis. |
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Lipase peaks... |
At 72 to 96 hours and remains elevated for several days (declines) |
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Substrate for lipase |
Olive oil |
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Pure reagent form of triglycerides |
Glycerol and 3 fatty acids |
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Classic method for triglyceride measurement |
Cherry Crandall hydrolysis of olive oil and titration of free fatty acids using dilute sodium hydroxide |
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Teitz methods |
24 hr incubation |
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Cherry method |
6 hour incubation |
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Turbidimetric method for lipase |
Measures reduction of turbidity |
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Trypsin |
Also synthesized in the acne cells of the pancreas as proenzyme trypsinogen |
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Trypsin is elevated in ____ and aids in diagnosis of ______ and _____ |
Pancreatic non function;fibrocystic disease |
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In cystic fibrosis there is a _____ in the secretion of trypsin by the pancreas |
Decrease |
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Specimens for trypsin measurement |
Aspiration of duodenal fluid or fresh feces |
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Normal values for stool (trypsin) |
Infants <1yr 1:80 older children 1:20/1:40 fibrocystic pts 1:32/64 |
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Normal values for duodenal fluids (trypsin) |
Infants 1:32/64 or > fibrocystic patients <1:4 |
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CPK rises within ____. Peaks _____ and returns to normal ______ |
4-6 hours after onset of pain, 24-36 hours, in 3 days |
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Pseudocholinesterase |
Insecticide (organophosphate) poisoning is the clinical significance. |
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Enzymes in rbcs are measured for this by |
Enzyme inhibition and the inhibition is proportional to the amount of exposure to the insecticide |
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method - trypsin by x-ray film |
fresh stool specimen diluted with saline for 1:5 to 1:320. Each dilutionis dropped on old unexposed x-ray film along with controls. |
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x-ray film technique: Incubated for |
30 minutes at 37 degrees. |
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Prostatic enzymes: acid phosphatase |
group of related enzymes found in the liver, spleen, milk, rbcs, platelets, bone marrow, and prostate gland. |
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How much of the acid phosphatase comes from the prostate |
1/3 to 1/2 |
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Optimum ph for acid phosphatase |
5.0 |
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Prostatic specific antigen (PSA) is a |
glycoprotein only produced by the prostate gland and is now used to screen for prostatic cancer. |
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Serum determinated is usually requested for diagnosis of _______ ________ with ______ |
prostatic carcinoma; acid phosphatase |