medchem 22 Flashcards
- peptides , polypeptides and proteins are – for alpha amino acids
- peptide generally contains fewer than — amino acids
- polypeptide contains as many as —
- a polypeptide or complex of polypeptide that has a 3d structure is —
- polymers
- 20-30
- 4,000
- protein
— are ubiquitous in living organisms and are involved in all body functions such as: transport of molecule and signalling
peptide ( its also amide combinig amino group of one amino acid with carboxyl group of another )
( dipeptides are Gly-Gly)
- 3 amino acids is referred to as –
- 4 amino acids —
- 5 amino acids —
- tripeptide ( as: gamma glu-cys-gly)
- tetrapeptide ( as: arg-gly-asp-ser)
- pentapetide ( as: tyr-gly-gly-phe-met)
the – of the amino acid is commonly used to identify the peptide
and its a – letter code or – code for each amino acid
- sequence
- 3-letter or 1 letter codes
– of amino acids are macromolecules formed by polymerisation of alpha amino acids which consist of : —- and —-
- polymers
- backbone consisting of linear chain of alpha amino acids
- side chains/groups which branches of the backbone which provided variety of functions according to the alpha amino acid selected
-in peptides the one amino acid remains with a free amino acid — –and the another amino acid remains free with carboxyl group —-
- amino acids in peptide sequence are called —-
- N-terminal residue ( left hand side)
- C-terminal reside ( right hand side )
- residues
– are covalent bonds in peptide formed between the side groups of two cysteines
- disulfied bonds which can be formed on the same peptide chain as vasopressin and oxytocin or in different peptide chain as insulin
the structural units of proteins are polymers of higher molecular wight is called —
polypeptide
( a protein can consist of one or many of polypeptide units)
the two types of proteins:
— is a structural protein that’s insoluble in eater as ——
—- are soluble in water and almost spherical shape
1- fibrous
as: alpha and beta sheets , keratins which makes up the protective tissue of the skin and hair , collegen which makes up the connective tissue of bones and silks as fibrion of spider webs
2- globular
as: enzymes aka biological catalysts , hormones aka chemical massagers , transport proteins as haemoglobin and myoglobin
the overall structure/shape of the protein is essential for —
function , as protein structures are 4
primary structure refers to:
The most fundamental level of protein structure: the sequence of covalently linked amino acids in the polypeptide
This sequence will ultimately determine the overall three dimensional shape of the protein
what gives the proteins the stability:
- restricted rotation which allows the 3d structure to be defined
- unreactive amide bind
secondary structure
-Once the cell makes the covalent amide bonds that link the specific
sequence of amino acids to give the polypeptide, non-covalent forces such as hydrogen bonding and hydrophobic interactions determine how a polypeptide twists into a particular 3-D shape.
-Hydrophobic interactions drive the formation of the overall shape
and hydrogen bonding stabilises it.
- the hydrogen boding is the force of attractive between partially +ve hydrogen and partially -ve oxygen of the carbonyl
- gives rise to alpha and beta sheeted structure
—- refers to the overall 3d repeating pattern as —-
and it involves —
- secondary structure
- alpha helix and b-pleated
- non-covalent forces as hydrogen bonds which determines how the polypeptide strand interact w/ themselves and others in oils and interwined or line up side by side
in —– the polypeptide backbone coils as a right handed screw.
Hydrogen bonds extend from the H atoms of the NH units to oxygen atoms of carbonyl units situated four residues farther along the polypeptide backbone
- alpha helix
and there are 3.6 amino acid residues per turn and each carbonyl ( c=o ) is hydrogen bonded to an NH further along the chain
