i need help quickly in biochemistry!!! PLEASE HELP!?

Question

i have a few questions to ask about....

Amino Acids:
1. What does the R group represent in the general formula for amino acids?
2. If the R goup is a methyl group (CH4) what amino acid is formed?

Enzymes
1. In what ways does an enzyme affect the reaction it catalyzes? How does the enzyme produce this effect?
2. What factors may affect enzyme activity?
3. What is the active site of an enzyme?

Answer 1

The R group represents the "side group of the amino acid." Depending on the R group (it can be methyl, carboxylic acid, amine), the amino acid will be categorized as acidic, basic, polar, etc. if the group is a methyl group, the AA is called alanine.

Enzymes affect the reaction rate by lowering the activation energy of the reaction. Note, this affects the kinetics (rate) of the reaction and not the thermodynamics. The enzyme produces this effect by binding to the substrate. Factors affecting enzymatic activity include temperature (high temp denatures enzymes and decreases rate, as well as pH). The active site of the enzyme is where the substrate binds.

Hope that helped. Let me know if you have any other questions.

Answer 2

1. R is the group attached to H2N-CH-COOH.
2. If R is CH3, then CH3CH(NH2)COOH is alanine

1. Enzymes speed up reactions. Also, if the substrate is chiral ("optically active"), then the enzyme acts on one optical isomer. Or, it produces only one optical isomer out of a possible two.
2. How closely the substrate fits. Whether the enzyme has been denatured ("ruined"). Temperature, pH, presence of a cofactor.
3. This is a molecular "pocket that the substrate fits in. The pocket is lined with groups like -OH, -COOH, -NH2, or metal ions that hold onto various groups in the substrate.