CHEM

active enzyme site

• Small part of an enzyme’s structure that is involved in catalysis.
• A three – dimensional entity formed by groups that come from different parts of the protein chains

enzyme-substrate complex

• The intermediate reaction species that is formed when a substrate binds to the active site of an enzyme.

lock and key model

ENZYME ACTION
lock and key model

induced fit model

•Enzyme’s active site is not rigid and static.
•There’s a constant change in shape
•Allows for changes in the shape or geometry of the active site of an enzyme to accommodate a substrate.
•Result of the enzyme’s flexibility; it adapts the incoming substrate.

absolute

ENZYME SPECIFICITY
- reaction for 1 substrate
ex. urease, catalase

group

ENZYME SPECIFICITY
- reaction for substrate w the same functional groups
ex. hexokinase, carboxypeptides

linkage

ENZYME SPECIFICITY
- reaction for a particular chemical bond
ex. lipase, phosphatase

stereochemical

ENZYME SPECIFICITY
- reaction for a particular stereoisomer
ex. isomerase

absolute, group, linkage, stereochemical

ENZYME SPECIFICITY

enzyme and substrate concentration
temperature
pH

FACTOR INFLUENCING ENZYME ACTIVITY

turnover number

•Number of substrate molecules transformed per minute by one molecule of enzyme under optimum conditions of temperature, pH and saturation of the substrate. •Ex. Catalase: 5,600,000
Lactate dehydrogenase: 60,000 DNA Polymerase I: 900

ENZYME INHIBITION - inhibitors

•Slows or stops the normal catalytic activity of the enzyme
•Change the protein structure of an enzyme
•May be competitive or noncompetitive
•Some effects are irreversible

a competitive inhibitor (competitive inhibition)

•Has a structure similar to substrate
•Occupies active site
•Competes with substrate for active site
•Has effect reversed by increasing substrate concentration

noncompetitve inhibitor

•Does not have a structure like substrate
•Binds to the enzyme but not active site
•Changes the shape of enzyme and active site
•Substrate cannot fit altered active site
•No reaction occurs
•Effect is not reversed by adding substrate

irreversible inhibitor

•Inactivates enzymes by forming a strong covalent bond to an
amino acid side-chain group at the enzyme’s active site
•Does not reverse the inhibition process
•Enzyme is permanently deactivated
•Effect is not reversed by adding substrate

negative and positive feedback

feedback regulation (2)

negative feedback

FEEDBACK REGULATION (2)
- pathway is inhibited by accumulation of final product

positive feedback

FEEDBACK REGULATION
– a regulatory molecule stimulates the activity of the enzyme, usually between 2 pathways

•Used to diagnose certaindiseases.
•Appearance of these enzymes in the blood often indicates
that there is tissue damage in an organ and that cellular contents are spilling out into the bloodstream.
•Used in the treatment of disease.

medical uses of enzymes

life

vita means

general characteristics of vitamins

• Organic compounds
• Must be obtained from dietary sources
• Human body can’t synthesize in enough amounts
• Essential for proper functioning of the body
• Needed in micro and milligram quantities (per day 50200g)
• 1 Gram of vitamin B is sufficient for 500,000 people

water soluble and fat soluble

2 classes of vitamins

tablet

synthetic vitamins

13

how many known vitamins

9

how many known water soluble vits.

4

no. of known fat soluble vitamins

B1,B2,B3,B6,B9,B12,B5,B7 VITAMIN C

WATER SOLUBLE VITAMINS (9)

ascorbic acid

vitamin c known as

vit c

-simples form/structure among 13
-oxidized and reduced form
- 1933
- cyclic ester (C1-carbonyl grp → c4 hydroxyl)
- no acid in structure
- maintains iron in oxidation state
- acts as antioxidant - vitamin e regenerated by VitC; - folate- helps active form..
- norephinephrine and thyroxine – hormones product of reaction ..
- best source -citrus fr, pepper, cauliflower, spinach,
cabbage

90mg/day-male
75 mg/day-female

recommended RDA

vit b

-components of coenzymes
-decarbonization

thiamin

PREFERRED NAME: B1

riboflavin

PREFERRED NAME: B2

niacin

PREFERRED NAME: B3

pyridoxine, pyridoxal, pyridoxamine

PREFERRED NAME: B6

folate/folic acid

PREFERRED NAME: b9

cobalamin

PREFERRED NAME: b12

pantothenic acid

PREFERRED NAME: b5

biotin

PREFERRED NAME: b7

cyanosis

B1 DEFICIENCY: lungs and heart

dyspnea

B1 DEFICIENCY: shortness of breath

diarrhea and vomiting

B1 DEFICIENCY
children

beriberi

B1 DEFICIENCY
adults, cardiovascular and nerbous system

Wernicke-Kosakoff

B1 DEFICIENCY
memory disorder

roboflavin (b2)

VITAMIN B
– has ribose
– found in meat, organ l
- redox reaction
- “yellow vitamin”

not part of bcomplex

B4-adenine
B8- Inositol
B10- para amino benzoic acid (PABA)
B11- salicylic acid

Vitamins A, D, E, K

Fat soluble vitamins (4)

fat soluble vitamins

• Involved in plasma membrane processes
• More hydrocarbon like with fewer functional groups

VITAMIN A

FAT SOLUBLE
– Has role in vision - only 1/1000 of vitamin A is in retina
– 3 Forms of vitamin A are active in the body
– Derived from b-carotine

VITAMIN D

• Two forms active in the body: Vitamin D2and D3
• Sunshine Vitamin: Synthesized by UV light from sun
• It controls correct ratio of Ca and P for bone mineralization (hardening)
• As a hormone it promotes Ca and P absorption in intestine

vitamin e

• Four forms of Vitamin Es: a-, b-, g- and d-Vitamin E • Alpha-tocopherol is the most active biological active form of Vitamin E
• Peanut oils, green and leafy vegetables and whole grain products are the sources of vitamin E
• Primary function: Antioxidant – protects against oxidation of other compounds

vitamin k

• Two major forms; K1and K2
• K1 found in dark green, leafy vegetables
• K2is synthesized by bacteria that grow in colon
• Dietary need supply: ~1/2 synthesized by bacteria and 1/2 obtained from diet

k1

VITAMIN K
- found in dark green, leafy vegetables

vitamink2

VITAMIN K
-synthesized by bacteria that grow in colon

phosphorus

•Functions: Bones and teeth accompanied by calcium,
muscle contraction
•Sources: Dairy products, nuts, meat, fish, oats, cocoa

IRON

•Functions: Production of hemoglobin in red blood cells
to carry oxygen in the blood
•Sources: Red meat, liver, eggs, bread, green vegetables
•Deficiency: Anemia

calcium

•Functions: Teeth and bones, blood clotting, nerve and muscle contraction, heart regulation
•Sources: Dairy products, fortified white bread, green vegetables, nuts and seeds
•Deficiency: Stunted growth can cause rickets and osteoporosis

sodium

•Functions: Maintains water balance in the body and
controls
body temperature, helps you sweat when body
temperature rises
•Sources: Cheese, smoked meats, fish, table salt,
•Deficiency: deficiency is highly unlikely

POTASSIUM

•Functions: Muscle contraction and in maintaining body fluid.
It is necessary for the building of muscle and for normal body growth.
•Sources: Banana, celery, meat, fruits, milk, grains, legumes,
raisins, dates, figs
•Deficiency: dry skin, acne, muscle spasms or weakness

zinc

•Functions: Aids the immune system. Cofactor in enzymes.
Needed for the senses of smell and taste
•Sources: Meat esp. lamb meat, oats, eggs, nuts
•Deficiency: Retarded growth
•Excess: Enlarged liver

iodine

•Functions: Thyroid gland function (controls how quickly the
body uses energy) and body metabolism
•Sources: Milk, eggs, yogurt, seafood, iodized salt •Disease involved Goiter

magnesium

•Functions: muscle contraction, DNA synthesis, controls
blood sugar and blood pressure, cofactor of enzymes
•Sources: Cheeses, cocoa, chocolate, nuts, beans
•Deficiency: hypocalcemia

optimal temp

where most enzyme Temp similar to normal body temp

buffers

maintain optimum pH in enzymes

saturation curve

enzyme activity increases bc of certain concent and remain constant

alosteric site

where noncompetitive inhibitor binds to enzyme

500,000 people

1 gram of vit B sufficient for

1 microgram

microgram (vit12 ) per day

1933

yr vit c is characterized

c1 carbonyl grp --> c4 hydroxyl

reaction (cyclic ester) forming ring

scurvy

long term devicieny (vit c)

Riboflavin (b2)

DEFICIENCY:
angular sumatitis
dermatitis
photophobia
neurological disorder

niacinc (b3)

DEFICIENCY:
pellagra

b6 (pyrido-)

DEFICIENCY:
irritability
seizure
facial sebora

b9 (folate/folic acid)

DEFICIENCY:
megaloblastic anemia

pteroylglutanic acid

folate/folic acid known as

b12 (cobalamin/cyocobalamin)

megaloblastic anemia

b5 (pantothenic acid)

DEFICIENCY:
depression, muscle weakness

b7 (biotin)

DEFICIENCY:
dermatits, anorexia, peripheral vasoconstriction

- Vision
- regulating cell differentiation
- maintenance of healthy epithelial tissues
- reproduction/growth

functions of vitamin A

vitamin a

DEFICIENCY:
night blindness
drier/harder surfaces

vitamin D

DEFICIENCY:
ricketts - children
osteomalacia - adults

D2 - ergocalciferol
D3 - cholecalciferol

2 forms of VIT D

alpha- beta- gamma- delta- (TOCOPHEROL)

4FORms of VIT E

lungs

vit e what organ

a-tocopherol

most active vit e

g=tocopherol

vit e rich foods

vitamin e

DEFICIENCY:
mild hemolytic anemia - infants
ataxia

K1 - phylloquinones (saturated, in plants)
k2 - menaquinones (animals)

2 forms vit k

vit k

DEFICIENCY:
hemorrhage
post traumatic bleeding

MAJOR MINERALS

Calcium
phosphorus
potassium
sulfur
chlorine
sodium
magnesium

TRACE ELEMENTS

iron zinc copper manganese
iodine
selenium

hypocalcemia

DEFICIENCY:
in calcium

hypophosphatemia

DEFICIENCY:
in phosphorus

hyponatremia

decrease H2O in sodium

potassium in, sodium out

PISO

hypokalemia

DEFICIENCY:
in potassium

hypomagnesemia

DEFICIENCY:
magnesium

goiter

enlrgement thyroid gland

Friedrich Miescher (1869)

discovered nucleic acid