Enzymes Study guide

Inorganic activators

Cofactors

the most common in oraganic activators are

• Cu

• Fe

• Mg

• Mn

• Zn

• Ca

Coenzymes are mostly

Organic vitamins

Hoe do coenzymes bind

loosley

Prosthetic group

An organic cofactor tightly or covalently bound to an enzyme to aid in catalyzing a reaction

Apoenzyme

an inactive protein or enzyme

Holoenzyme

the enzyme portion with its respective coenzyme, forming a complete and active system

What are four factors affecting enzyme reaction

• substrate concentration

• enzyme concentration

• Ph

• temp

1st order

the rate of reaction is directly proportional to the substrate concentration

0 order kinetics

The rate depends on the enzyme concentration only

• most ideal for measuring enzyme activity

• lareg excess substrate so the amount of enzyme is the only rate limitor

One international unit of enzyme activity is

1umol/min

Michalis menten constant is

Km=1/2V

in a line weaver burk plot y intercept

1/Vmax

In a line weaver burk plot what is the x intercept

-1/Km

What are the three kinds of enzyme inhibitors

• competative

• uncompetative

• noncompetative

competitive inhibitor

can bind to an active site and competes with substrate. it can be over come with more substrate

Noncompetitive inhibitor

bind at another site and do not compete with the substrate and can be reversible, alters the enzyme structure so it cant bind to anything

Uncompetitive

binds to the Enzyme substrate complex brining the reaction to a grinding halt

• additional substrate increases inhibition

Fixed time monitoring

• reactants are combined

• Rxn proceeds for defined period

• Rxn is stopped

• measurment of chromogen is made

Continuous monitoring

• multiple measurements during the rxn

• usually absorbance changes

• specific intervals

• continuously recording spectrophotometer

ALT

released when liver is damaged

AST

released when liver is damaged

ALP

cystolic- hepatobiliary, released when there is a hepatobiliary obstruction

GGT

cystolic- hepatobiliary, released when there is a hepatobiliary obstruction

macroamylase

disease defined by the elevation in serum amylase activity due t the precense of complex macromolecules whose huge size inhibits their elimination via the urinary system

macroamylase presents as

unable to excrete amylase, so hyperamylasemia

How are most enzymes tested for

spectroscopic techniques, specifically absorption and fluorescence measurements

LD

Converts pyruvate to lactate while oxidizing NADH to NAD

How is LD measured

rate of decreased absorbance of NADH at 340nm is proportional to LD

ALP

found in the bone, intestinal mucosa, renal tubules, biliary tree, leukocytes, placenta and some tumors, increases when something is wrong or not exiting

Heat stability for ALP is used for

identifying the source of having an elevated ALP

What are the most heat stable enzymes

placental

what is the most stable isoenzyme associated with rare neoplasms

Regan and Nagao

What is the most heat liable enzyme

bone

ALP activity is measured before and after heating he serum, what temp is it heated to

56C for 10 min

CKBB

Brain, GI, prostate, uterus

CKMB

acute myocardial infarction

CKMM

Muscle injuries and heart

LD is hisotrically MI

“flipped isoenzyme pattern (LD1>LD2)