biochem mini 1b

rate is INdependent on [S]

rate dependent on concentration of one substrate

rate depends on contration of both substrates

• -1.5 g/L saturation
• - 10 g/hr limit
• - not specific for EtOH, will use MeOH as well, which is why you can tx methanol poisoning with EtOH

• neg- spontaneous (exergonic)
• pos- non-spontaneous (endergonic)
• 0- rxn at eq

• acid/base and nucleophilic/electrophilic changes
• -coenzymes aid other reactions, ie redox

• High energy PO₄ cpds (ATP,ADP etc)
• reduced coenzymes (NADH, FADH₂)

increase with the greater number of resonance referene structures

• -delta G^o = -7.3 Cal/mol
• -rxn requires Mg as cofactor
• - same E released in ADP + H2O -----> AMP + Pi

delta G = -10.9 Cal/mol

flavins- redox of C=C

nicotinamides- redox of C=O by transferring H^- (hydride ion), if H₂ used an H⁺ will end up in solution producing acid

• ez catalyzes one rxn for one S
• ex. UREASE

• ez catalyzed rxn involving only certain functional groups
• ex. carboxypeptidase

• ez catalyzes rxn for only a single bond type
• ex. phosphotases

means that ES is not perfect and it is more likely to break down to E + S than it is to go onto products (E+P)

• = k₂[E]
• to increase rate: add more E or improve k₂

V₀= Vmax/2

V₀=Vmax

V₀=Vmax/Km

every substrate that hits the enzyme causes a reaction

k_cat/Km = k₁

ex. ACh-esterase,CA, triose PO4-isomerase (glycolysis

• irreversible ACh-esterase inhibitor
• -irreversible inhibitors form TRUE covalent bonds (often with ser residues) with the active site on an enzyme permanently inactivating it
• "suicide inhibitors"

• irrevrsible XO inhibitor
• xanthine----//----> urate

irreversible MAOI

• competitive inhibitor of AD
• tx for MeOH poisoning

means inhibitor affinity for enzyme will me much greater than S= good inhibitor

• competitive inhibition:
• -Km increases
• -Vmax unchanged
• - increases S can overcome inhibition
• -I competes with S for active site

• -noncompetitive inhibition
• -I binds at site OTHER than active site
• - large amounts of S can NOT overcome inhibition
• - Vmax decreases
• -Km unchanged

allosteric regulation and reversible covalent modification(ex. phosphorylation)

• -composed of 2 or more protein chains, often regulatory site on one and active site on another
• -can be upregulated or down regulated (A or I do not need to resemble S)
• -catalyze irreversible rxn
• -rate limiting

• A and I that bind to allosteric sites
• -are not identical to the substrate

• S acts as effector
• -induces allosteric effects when it binds the active site

• digests bacteria cell wall by breaking BETA (1-4) GLYCOSIDIC BONDS between NAM and NAG
• ** only effective against gram + bacteria**

• ** all have a SER, HIS and ASP at their catalytic center, aka "catalytic triad"**
• ** increased affinity with bulkyer side chain**
• -his acts as buffer and grabs a H+ from serines OH group leaving an O^-, which then attacks the peptide bond
• -ex. chymotrypsin

• ** 1/3 of all known ez need a metal ion to work**
• - metal either binds substrates to orient, redox, electrostatic stabilization or negative charge shielding

anaerobic- lactic acid

aerobic- pyruvic acid

• can be caused by defect in any glycolysis enzyme
• - G6PDH is most common
• -recessive autosomal PK def is second (inc 2,3-BPG)

• 3 NADH, 1 FADH2, 1GTP
• NADH and FADH2 are used in the ETC

ala, pyruvate and lactic acid

• -resupplies NAD+ to G-3-PDH reaction
• -pyruvate------> lactate
• -under anaerobic conditions

• **main regulatory ez in glycolysis**
• -irreversible(committing) and E consuming
• - enhancer- *F2,6-BP(dec Km), AMP
• -inhibitor-ATP-Mg

• brain- 120 g/day
• total- 160/day

• - specialized glucose specific HK w/ inc Km
• -found in liver and pancrease
• - irreversible, but not glycolysis committing Glu----> G6P (for glycogenolysis with GK)
• - not inhibited by its product G6P, unlike other HK's

• - oxidation in glycolysis
• - pentose PO4 p/w
• - glycogenolysis

• **requires NAD+ (resuppled by LDH)**
• - G3P----> 1,3 BPG

inhibitor of substate level phosphorylation (used by PGK(7) and PK(10))

enhances O2 release from RBC

• potent inhibitor of enolase (8)
• 2-PG ---//--> PEP

• HK (1)
• PFK-1 (3)
• PK (10)

• - consumes NAD+
• -can stop glycolysis and TCA
• - can cause HYPOglycemia by stopping gluconeogenesis
• -can cause acidosis by ketone metabolism

normal- 8/1

alcoholic- 1/1

HK, PFK-1, PK

• regulator of glycolysis
• - NO NEG. FEEDBACK BY G6P
• -

• regulator of glycolysis
• -F1,6-BP will enhance and increase I:G
• - ala and PO4 will inhibit

• positively regulates PFK-1 and PK
• inc I:G = low cAMP= low PKA activity= PFK-2 (unPO4)= PFK-2 kinase activity= increase F2,6-BP= increased PFK-1 activity= glycolysis stim for conversion on Glu to trigs

• synthesizes F2,6-BP (regulator of of PFK-1 in liver and adipose tissue)
• -has a ser group that can be PO4ed
• -PO4=PO4ase activity (in liver only)
• -nonPO4= kinase activity (high I:G)

inhibit glycolysis

• PO4 increases PFK-2*KINASE* activity, because heart is a consumer organ as opposed to the liver that is a maintainer organ.
• -so in the heart EPI increases glycolysis via increased cAMP cascade

• -ATP and ala inhibit
• -F1,6-BP allosterically activates
• -PO4 inactivates(only in liver form) via glucagon
• -**no ser on the SkM and CM forms, so it is not inactivated by PO4 in these tissues**