Biochemistry- Review- Amino acids properties

monomers

amino acids are the ___ making up proteins

alpha carbon

All amino acids share common structural features: an ___ and 4 substituents

chiral center

The alpha carbon is the ___ of the amino acid

tetrahedral

the alpha carbon of amino acids usually have a ___ structure

4 substituents of amino acids

• a carboxyl group (COO-)

• an amino group (NH3+)

• a hydrogen atom

• an R group (unique side chain)

glycine

only amino acid that has 2 hydrogen atoms connected to its alpha carbon instead of one hydrogen and a R group

L

Amino acids in our body are usually the __ enantiomer

alipathic

organic compounds that have an open-chain structure

relating to or denoting organic compounds in which carbon atoms form open chains (as in the alkanes), not aromatic rings.

nonpolar aliphatic R groups

• Glycine

• Alanine

• Proline

• Valine

• Leucine

• Isoleucine

• Methionine

aromatic R groups

• phenylalanine

• tyrosine

• tryptophan

Polar uncharged R groups

• serine

• threonine

• cysteine

• asparagine

• glutamine

Positively charged R groups

• Lysine

• Histidine

• Arginine

Negatively charged R groups

• aspartate

• glutamate

weak

amino acids can act as __ acids or bases due to their carboxyl groups and ionizable R chains

zwitterion

a molecule that contains both positively and negatively charged functional groups, with a net charge of zero

occurs at neutral pH for amino acids

isoelectric point

pH at which the net electric charge is 0

• where you find the zwitterion

more

alpha carboxyl group is __ acidic that in carboxylic acids

less

alpha-amino group is __ basic than in amines

buffers

amino acids can be used as ___

peptide bond

covalent bond formed through condensation and broken through hydrolysis, links 2 proteins together

oligopeptides

made of few amino acids

polypedtide

made of many amino acids

• weight<10 kDa

protein

1000s of amino acids

• molecular weight >10kDa

N-terminal

numbering and naming peptides start from the ___ aka amino-terminal residue

multisubunit protein

2+ polypeptides associated noncovalently

oligomeric protein

2+ identical subunits

protomers

identical units

structural units of an oligomeric proteins.

___ associates to make larger oligomer composed of 2 or more copies of this unit/___

conjugated protein

contains permanently associated chemical components

• lipoproteins

• glycoproteins

• metalloproteins

prosthetic group

non-amino acid part of the protein

primary structure

covalent bond linking amino acid residues in a polypeptide chain

secondary structure

recurring structural patterns

• Beta sheets

• Alpha helices

tertiary structure

3D folding of polypeptide

quaternary structure

2+ polypeptide subunits