Protein Techniques Reviews

Enzyme kinetics is the study of

study of the rates of enzyme-catalysed chemical reactions

study of the rates of enzyme-catalysed chemical reactions

Enzyme kinetics

monopeptide

single amino acid

dipeptide

two amino acids

What is the significance of the isoelectric point in protein solubility?

The isoelectric point (pI) is the pH at which a protein has no net charge. Proteins are least soluble at pI because electrostatic repulsion is minimized, leading to aggregation and precipitation.

pH at which a protein has no net charge

isoelectric point (pI)

Describe the use of pH titration curves to determine the pKa of amino acids.

Titration curves plot pH against added titrant volume. The pKa is determined at the midpoint of the buffering region where half of the amino acid's acidic groups are deprotonated. This inflection point corresponds to the pKa value.

Compare bacterial expression systems with mammalian cell systems.

Bacteria are rapid and economical but lack post-translational modifications; mammalian cells produce more authentic proteins but are costlier and slower.

How does fermentation optimize protein yield?

It controls parameters like pH, oxygen, nutrients, and temperature to maximize cell growth and protein expression.

hydroxyl properties

polar

methyl properties

nonpolar

carbonyl properties

polar

sulfhydryl properties

polar

carbonxyl properties

charged, ionizes to release H+, since carboxyl groups can release H+ ions into solution, they are considered acidic.

phosphate properties

charged, ionizes to release H+, since phosphate groups can release H+ ions into solution, they are considered acidic.

amino properties

charged, accepts H+ to form NH3+, since amino groups can remove H+ ions into solution, they are considered basic.

hydroxyl structure

ROH

methyl structure

RCH3

carbonyl structure

C=O

carboxyl structure

O=COH

sulfhydryl structure

RSH

Acids that can donate more than one proton are called

polyprotic acids

polyprotic acids

Acids that can donate more than one proton

buffer

solution containing a weak acid and its conjugate base in comparable concentrations

solution containing a weak acid and its conjugate base in comparable concentrations

buffer

To maintain homeostasis, humans regulate their pH levels between

7.35 and 7.45.

Alanine single letter code

A

Alanine three letter code

Ala

Glycine single letter code

G

Glycine three letter code

Gly

Isoleucine single letter code

I

Isoleucine three letter code

Ile

Leucine single letter code

L

Leucine three letter code

Leu

Proline single letter code

P

Proline three letter code

Pro

Valine single letter code

V

Valine three letter code

Val

Phenylalanine single letter code

F

Phenylalanine three letter code

Phe

Tryptophan single letter code

W

Tryptophan three letter code

Trp

Tyrosine single letter code

Y

Tyrosine three letter code

Tyr

Aspartic Acid single letter code

D

Aspartic Acid three letter code

Asp

Glutamic Acid single letter code

E

Glutamic Acid three letter code

Glu

Arginine single letter code

R

Histidine single letter code

H

Histidine three letter code

His

Lysine single letter code

K

Lysine three letter code

Lys

Serine single letter code

S

Serine three letter code

Ser

Threonin single letter code