1 mM and 0.4 mM/min

4 mM and 0.49 mM/min

6 mM and 0.33 mM/min

4 mM and 0.5 mM/min

2 mM and 0.5 mM/min

In Gram- negative cell walls, a pentaglycine chain bridges the lysine ε-amino group and the D- Ala carboxyl group.

The backbone is a β(1→4)-linked polymer of N-acetylglucosamine and N-acetylmuramic acid units.

The backbone N-acetylmuramic acid units are joined to a tetrapeptide, usually L-Ala•D-Glu •L-Lys • D-Ala, in which the L-lysine is linked to the Υ-COOH of D-glutamate via its D-lactate moiety.

In Gram-positive cell walls, the lysine ε-amino group forms a direct amide bond with this D- alanine carboxyl.

a. The hydrogen is centered between the two heteroatoms and the interactions are more covalent.

b. In the chymotrypsin reaction mechanism; LBHB formation takes place between Asp102 and His57.

d. The barrier that the hydrogen atom must surmount to exchange oxygens becomes lower.

e. All are true.

c. The bond order approaches 0.5 for both O−H interactions.

His57 acts as a general base to withdraw a proton from Ser195, facilitating nucleophilic attack by Ser195 on the carbonyl carbon of the peptide bond to be cleaved.

The amide nitrogens of Ser195 and Gly193 form an “oxyanion hole” in which the substrate carbonyl oxygen is hydrogen bonded to the amide N-H groups to stabilize the oxyanion transition states.

The kinetic pattern obtained on hydrolysis of p-nitrophenylacetate by chymotrypsin is consistent with rapid formation of an acyl-enzyme intermediate (and the burst of nitrophenolate).

Direct deprotonation of water by His to generate a hydroxide ion for initiation of the reaction

The slower, steady-state release of products corresponds to rate limiting hydrolysis of an acyl-enzyme intermediate to complete the reaction.

Agar is an important polysaccharide mixture isolated from marine red algae (Rhodo- phyceae), which consists of two components, agarose and agaropectin.

The three-dimensional structure of agarose is a double helix with a threefold screw axis.

Agarose is a chain of alternating D-glucose and 3,6-anhydro-L-glucose, with side chains of 6-methyl-D-galactose.

The central cavity is large enough to accommodate water molecules allowing agarose and agaropectin to readily form gels containing large amounts (up to 99.5%) of water.

Agaropectin is similar, but in addition, it contains sulfate ester side chains and D-glucuronic acid.

The ratios of A and B subunits differ depending upon the tissue type

The amount of subunit phosphorylation differs.

They have differing Km values for lactate.

They have different kinetic parameters.

They have differing Km values for pyruvate.

Ser-His-Asp

Cys-His-Ser

Ser-His-His

His-Ser-Asp

Asp-His-Ser

covalent nucleophilic catalysis.

covalent electrophilic catalysis.

general base catalysis.

specific base catalysis.

low barrier hydrogen bond catalysis.

N; galactose; fucose; N-acetyl galactose; N-acetyl galactose; galactose

O; glucose; fucose; N-acetyl galactose; N-acetyl galactose; glucose

N; glucose; fucose; N-acetyl glucose; N-acetyl glucose; glucose

N; glucose; fucose; N-acetyl galactose; N-acetyl glucose; glucose

O; galactose; fucose; N-acetyl galactose; N-acetyl galactose; galactose

Vitamin B12/Cyanocobalamin, ester, arginine

Vitamin E/Tocopherol, amide, lysine

Vitamin B2/Pyridoxal phoshphate, schiff base, asparagine

Vitamin B6/Pyridoxal phosphate, schiff base, lysine

Vitamin B6/Thiamine pyrophosphate, schiff base, arginine

Formation of the transition state always assures that the reaction will proceed to product.

Binding of substrate to an enzyme often causes strain, thus promoting transition state formation.

The energy barrier between ES and EX‡ is less than the energy barrier between S and X‡ .

The enzyme stabilizes the transition-state complex more than it stabilizes the substrate complex.

The enzyme is "designed" to bind the transition-state structure more tightly than the substrate or product.

AMP: negative heterotropic effector

phosphorylation: covalent inhibitor

glucose-6-phosphate: negative heterotropic effector

phosphate: positive heterotropic effector

ATP: positive heterotropic effector

allosteric regulation.

enzyme destruction.

covalent modification

activation of a zymogen.

enzyme induction.

O-α-D-glucopyranosyl- (1→3)-O-α-D-fructofuranosyl-(2→1)-β-D-glucopyranose, reducing

O-α-D-glucopyranosyl- (1→6)-O-α-D-fructofuranosyl-(1→2)-β-D-glucopyranose, non-reducing

O-α-D-galactopyranosyl- (1→6)-O-α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside, reducing

O-α-D-glucopyranosyl- (1→4)-O-α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside, non-reducing

O-α-D-galactopyranosyl- (1→3)-O-α-D-glucopyranosyl-(2→1)-β-D-fructofuranoside, non- reducing

Folate/THF

Biotin

NAD+/NADH

FAD and FMN

Coenzyme A