Enzyme regulation

enzymes

protein catalysts

increase rate of reaction

enzyme function

active site

The part of an enzyme where the chemical reaction occurs.

substrate binding

enzymes have a high affinity or high degree of specificity for a substrate

catalysis

the acceleration of a chemical reaction by a catalyst

Apoenzyme

protein portion of enzyme catalytically inactive by itself

catalytic site/ active site

site where enzyme binds substrate

coenzyme

nonprotein small organic molecule

cofactor

nonprotein metal enzymes

holoenzyme

Enzyme and nonprotein components catalically active

reduce activation energy

what does an enzyme change about a reaction?

substrate, temperature, enzyme concentration, pH

what factors affect kinetic properties of enzymes

maximum rate at which product is created with a given amount of enzyme

Vmax

concentration of substrate required to produce half Vmax

Km

higher Km=lower affinity for substrate

relationship between Km and affinity of substrate

increases when enzyme concentration increases

relationship between Vmax and enzyme concentration

competative inhibitor

affected by concentration, competes with substrate for binding site

non-competative inhibitor

Not affected by concentration, changes shape of active site by binding elsewhere.

Amylase

Enzyme in saliva that hydrolyzes bonds in starches into glucose and maltose

parotid gland (salivary gland)

where is salivary amylase mainly produced?

acute pancreatitis

what is indicated when lipase and amylase levels are elevated in serum

alanin/aspartate aminitransfeerase

catalyze transfer of an amino group from an amino acid to a-ketoglutarate

liver damage

what does elevate ALT/ AST indicate

creatine phosphokinase (CPK)

found in heart, brain, and skeletal muscles. leaks into blood when muscle tissue is damaged

stress or injury of heart or other muscles

what does elevated levels of CPK indicate?

Lupus

what disease can be associated with elevated CPK levels

galactose-1-phosphate Uridyltransferase (GALT)

This enzyme is needed for the conversion of galactose.

Galactosemia

inability to metabolize galactose due to non-functional GALT

salivary amylase

which enzyme would be useful to assess radiation damage of salivary glands

ketones in urine and elevated galactose

what is a measurable indicator of galactosemia?

Damage to Salivary Glands

what does elevated levels of amylase but not lipase indicate?

AST/ALT ratio

enzyme valuable for assessing extent of liver damage/injury

in presence of competitive inhibitor

when does Km increase

decreases when non-competative inhibitor is present

with what inhibitor does Vmax change and does it increase or decrease?

non competitive

what kind of inhibitor?

competitive inhibitor