Biochem general

Eco ri methylase

Not a restriction endonuclease

isoelectric point

the specific pH where a molecule (protein/ amino acid) has no net electrical charge

pH value below isoelectric point

proteins arent negatively charged

Michaelis menten model

DOESNT assume the formation of a covalent intermediate between enzyme and substrate

standard alpha helix

3.6 amino acid residues per turn

bacteria transformed with the vector pBR322

grow in the presence of ampicillin

bond that joins nucleotides in RNA

phosphodiester bonds

suitable units for specific activity

micro mole of product/min/mg protein

when are membrane proteins usually inactive

in gel phase lipid

how does N-linked glycosylation occur

primarily via the amide nitrogen atom of asparagine residues

where is peptidoglycan present

cell walls of both gram positive(much thicker) and gram negative bacteria

Beta-mercaptoethanol function

reduce disulphide bridges

T4-DNA ligase requires what for its action

ATP

what can membrane proteins contain

beta barrels

how does lactose get digested in the absemce of glucose

lactose converted to allolactose- bind to lac repressor, changing shape and preventing access to operons genes- turns them on to digest lactose

what reduces disulphide bridges

Beta-mercaptoethanol

Type 2 restriction enzymes

cleave at their specific recognition sites in DNA

ninhydrin

turrns yellow when amide groups present

where does amino acyl-tRNA bind in ribosome

A- site

peptide bond property

planar

cellulose

polymer of glucose monomers joined by beta- linkages

how many residues does a transmembrane alpha helix contain

20

Michaelis menten model assumes what?

E«S

direction of protein synthesis

from amino (N) terminus to the carboxyl (C ) terminus

Electrophoresis in absence of SDS

separates molecules according to their charge and mass

Trypsin

cleaves proteins on the carboxyl side of lysine or arginine residues

Alpha helices are destabilised by what?

glycine residues

RNA polymerase initiates synthesis of mRNA how?

bind to promoter region

how are alpha helices staabilised

by hydrogen bonds between residue x and residue x+ 4

Expression vectors

used to make eukaryotic proteins in prokaryotic hosts

Maximum rate of reaction (Vmax )

• the point where all the active sites are bound to substrate (enzyme is saturated)

• reflects how fast the enzyme can catalyse the reaction

• if a low value- enzyme does not convert much substrate to product per unit time when enzyme saturated with product

Michaelis constant (Km)

• the substrate concentration which is equal to half its maximum value

• a low value means only a small amount of substrate is required to saturate the enzyme indicating high affinity for the substrate