ENZYMES AND VITAMINS Flashcards
1
Q
- are catalysts and are not consumed in the reactions
- are proteins that act as a catalyst for biochemical reactions
A
Enzymes
2
Q
composed only of protein (amino acid chains)
A
Simple enzyme:
2
Q
Has a nonprotein part in addition to a protein part.
A
Conjugated enzyme:
3
Q
Apoenzyme + cofactor =
A
holoenzyme
3
Q
: Protein part of a conjugated enzyme.
A
Apoenzyme
3
Q
- catalyzes a hydrolysis reaction
A
Hydrolase
3
Q
Nonprotein part of a conjugated enzyme.
A
A cofactor
3
Q
- catalyzes an oxidation reaction,
A
Oxidase
4
Q
A __________ is the biochemically active conjugated enzyme
A
holoenzyme
4
Q
o : effects the removal of the components of water from a double bond
A
Dehydratase
4
Q
o Involves a particular type of bond irrespective of the structural features in the vicinity of the bond
o Considered most general of enzyme specificities
A
- Linkage Specificity:
5
Q
- are important for the chemically reactive enzymes
A
Cofactors
5
Q
- An ____________ enzyme catalyzes an oxidation–reduction reaction:
o Oxidation and reduction reactions are always linked to one another
A
Oxidoreductase
5
Q
o - catalyze transfer of an amino group to a substrate
A
Transaminases
5
Q
- A ____________ is an enzyme that catalyzes the transfer of a functional group from one molecule to another
- Two major subtypes:
o Transaminases
o Kinases
A
Transferase
5
Q
o - catalyze transfer of a phosphate group from adenosine triphosphate (ATP) to a substrate
A
Kinases
5
Q
- A _____________ is an enzyme that catalyzes the addition of a group to a double bond or the removal of a group to form a double bond in a manner that does not involve hydrolysis or oxidation
A
Lyase
5
Q
- An ___________ is an enzyme that catalyzes the isomerization (rearrangement of atoms) reactions.
A
isomerase
5
Q
- A __________ is an enzyme that catalyzes a hydrolysis reaction
A
Hydrolase
5
Q
o Enzyme has a pre-determined shape for the active site
A
Lock-and-Key model:
5
Q
- A _________ is an enzyme that catalyzes the formation of a bond between two molecules involving ATP hydrolysis:
A
ligase
5
Q
o : effects the addition of the components of water to a double bonds
A
Hydratase:
5
Q
- the concentration at which it reaches its maximum rate and all of the active sites are full
A
Substrate saturation:
5
Q
- Number of substrate molecules converted to product per second per enzyme molecule under conditions of optimum temperature and pH
A
Turnover Number
5
*: At a constant enzyme concentration, the enzyme activity increases with increased substrate concentration.
Substrate Concentration
5
continually produces large amounts of an enzyme and plentiful amounts of products if the processes are not regulated.
Cellular processes
5
a substance that slows down or stops the normal catalytic function of an enzyme by binding to it.
Enzyme Inhibitor:
5
Compete with the substrate for the same active site
* Competitive Inhibitors:
5
* An ____________ inactivates enzymes by forming a strong
covalent bond with the enzyme’s active site.
Irreversible Inhibition
6
o Some regulators increase enzyme activity –
activators
7
o Some regulators decrease enzyme activity -
inhibitors
8
o ___________ is often derived from an ATP molecule.
Phosphate group
8
* A process in which activation or inhibition of the first reaction in a reaction sequence is controlled by a product of the reaction sequence.
Feedback Control
9
are “turned
on” at the appropriate
time and place
Zymogens
11
* Many derivatives of sulfanilamide collectively called sulfa drugs exhibit antibiotic
activities
Sulfa Drugs
12
* is structurally similar to PABA (p-aminobenzoic acid)
* is a competitive inhibitor of enzymes responsible for converting
PABA to folic acid in bacteria
Sulfanilamide
13
* Accidently discovered by Alexander Fleming in 1928
Penicillins
14
* Considered the best broad-spectrum antibiotics because it is effective against skin and bone infections as well as against infections involving the urinary, gastrointestinal, and respiratory systems
* It is the drug of choice for treatment of traveler’s diarrhea
Cipro
16
Water-Soluble Vitamins
Vitamin C
Vitamin B
17
* The preferred and alternative names for the ____________
* Thiamin (vitamin B1)
* Riboflavin (vitamin B2)
* Niacin (nicotinic acid, nicotinamide, vitamin B3)
* Vitamin B6 (pyridoxine, pyridoxal, pyridoxamine)
* Folate (folic acid)
* Vitamin B12 (cobalamin)
* Pantothenic acid (vitamin B5)
* Biotin
* Exhibit structural diversity
* Major function: _______________ are components of coenzymes3
B vitamins
17
* Involved in plasma membrane processes
* More hydrocarbon like with fewer functional groups
Fat-Soluble Vitamins
19
Fat-Soluble Vitamins
Vitamin A, D, E, K
20
o Has role in vision - only 1/1000 of vitamin A is in retina
o 3 Forms of vitamin A are active in the body
o Derived from b-carotene
o Vision:
o Regulating Cell Differentiation - process in which immature cells change to specialized cells with function.
o Maintenance of the healthy of epithelial tissues via epithelial tissue differentiation.
Vitamin A
21
o Four forms of Vitamin _____ : a-, b-, g- and d-Vitamin E
o Alpha-tocopherol is the most active biological active form of _________
o Peanut oils, green and leafy vegetables and whole grain products are the sources of ___________
o Primary function: Antioxidant – protects against oxidation of other compounds
vitamin E
21
o Two forms active in the body: Vitamin D2 and D3
o Sunshine Vitamin: Synthesized by UV light from sun
o It controls correct ratio of Ca and P for bone mineralization (hardening)
o As a hormone it promotes Ca and P absorption in intestine
Vitamin D
21
o Two major forms; K1 and K2
o K1 found in dark green, leafy vegetables
o K2 is synthesized by bacteria that grow in colon
o Dietary need supply: ~1/2 synthesized by bacteria and 1/2 obtained from diet
o Active in the formation of proteins involved in regulating blood clotting
Vitamin K
22
o is synthesized by bacteria that grow in colon
K2
22
o found in dark green, leafy vegetables
K1
23
o An enzyme will catalyze a particular reaction for only one substrate
* Absolute Specificity:
25
o Substrate contact with enzyme will change the shape of the active site
* Induced Fit Model:
28
o Involves structurally similar compounds that have the same functional groups.
* Group Specificity:
29
* Enzymes are not consumed in the
reactions they catalyze
Enzyme Concentration
30
o An enzyme can distinguish between stereoisomers.
* Stereochemical Specificity:
39
A process in which enzyme activity is altered by covalently modifying the structure of the enzyme:
o Involves adding or removing a group from an enzyme
Covalent modification:
41
* An _____________ is a substance that kills bacteria or inhibits their growth
Antibiotics
46
* Organic compounds
* Must be obtained from dietary sources
Vitamins
50
* Humans, monkeys, apes and guinea pigs need dietary vitamins
* Co-substrate in the formation of structural protein collagen
* Involved in metabolism of certain amino acids
* 100 mg/day saturates all body tissues - Excess vitamin is excreted
* RDA (mg/day):
Vitamin C
