proteins part 1 Flashcards
A highly complex substance that is present in all living organisms.
• They account for about 15% of a cell’s overall mass.
Protein
Dutch chemist found that egg and milk can be coagulated on heating and were
nitrogenous subtance
• Gerardus Johannes Mulder
suggested to Mulder that these substances should be called proteins
JJ Berzelius
from Greek word “__________” which means
“primary”, or “holding first place” or “preeminent”
from Greek word “proteios” which means “primary”, or “holding first place” or “preeminent”
Proteins are fundamental structural components of the body; nitrogeneous macromolecules composed of ___________________
Proteins are fundamental structural components of the body; nitrogeneous macromolecules composed of many amino acids
The proteins in the body are made up of
some combination of _________________
called _______________
The proteins in the body are made up of
some combination of 20 different subunits called amino acids.
______________ are always found in proteins
• it is an amino acid in which the amino group and the carboxyl group are
attached to the alpha carbon.
alpha amino acids are always
found in proteins
• alpha amino acid is an amino
acid in which the amino group
and the carboxyl g r o u p a r e
attached to the alpha carbon
All amino acid is isolated from proteins, with the exception of ____________, have the same general structure
• side chains vary in size, shape,
charge, acidity, functional group
present, hydrogen-bonding
ability, and chemical reactivity
All amino acid is isolated from proteins, with the exception of proline, have the same general structure
• side chains vary in size, shape,
charge, acidity, functional group
present, hydrogen-bonding
ability, and chemical reactivity
Any neutral molecule with equal number of positive and negative charges.
• Dipolar ions
• Amino acids in the presence of water becomes Zwitter ions
Zwitterion
These group of amino acid prefer to contact with one another rather than water and are said to be “hydrophobic amino acids” - water fearing.
-They are generally found buried in the interior of proteins, where they can associate with one another and
remain isolated from water.
Non-polar groups
- They are attracted to polar water molecules, they
are said to be “hydrophilic Amino acids” -water loving. - The hydrophilic side chains are often found on the surface of proteins.
Polar Group
- Have ionized carboxyl groups in their side chains. At pH7 these amino acids have a net
charge of -1. - They are acidic amino acids because ionization of the carboxylic acid releases a proton.
Negatively charge Amino Acids
At pH 7 these amino acids have a net positive charge because their side chains contain positive groups.
- These amino groups are basic because the side chain reacts with water, picking up a proton and releasing a hydroxide anion
• Positively charged Amino Acids
amino acids are minimally soluble at their
_______________
isoelectric points.
Those amino acids with longer alipathic side chains are ___________ than those with shorter chain polar groups such as carboxyl and hydroxyl, tend increase solubility.
Those amino acids with longer alipathic side chains are less soluble than those with shorter chain polar groups such as carboxyl and hydroxyl, tend increase
solubility.
Amino acids that are usually sweet:
(Gly, Ala, Val, Ser)
Amino acid that is tasteless:
(Leu)
Amino acid that is bitter
Iso
The aromatic amino acids ____________
absorb ultraviolet light.
W, Y and F
The alpha carbon of all amino acids except
____________ are asymmetric, so they show optical activity. The rotation of the amino acid vary according to the pH of the solution, which determines the ionic state of the amino acid
The alpha carbon of all amino acids except
glycine are asymmetric, so they show optical activity. The rotation of the amino acid vary according to the pH of the solution, which determines the ionic state of the amino acid
Depending on the pH of the solution, these groups act as proton donors (acids) or proton acceptors (bases). This property is called _____________ and therefor amino acids are called _____________.
Depending on the pH of the solution, these groups act as proton donors (acids) or proton acceptors (bases). This property is called amphoteric and therefor amino acids are called ampholytes.
the pH at which it occurs without any
charge on it. On the acidic side of its pl, amino acid exist as a cation by accepting a proton and on alkaline side as anion
by donating a proton.
p
pl or isoelectric pH
Some amino acids are converted to carbohydrates and are called ____________________
Some amino acids are converted to carbohydrates and are called glucogenic amino acids
______________ can synthesize a vitamin called niacin
Tryptophan can synthesize a vitamin called niacin
____________________ synthesize creatinine
Glycine, arginine, and methionine synthesize creatinine
_______________ help in synthesis of bile salts
Glycine and cysteine help in synthesis of bile salts
____________________ synthesize glutathione
Glutamate, cysteine, and glycine synthesize glutathione
_________ changes to histamine
Histidine changes to histamine
In addition to tripeptide formation, _______ is used for the synthesis of heme
In addition to tripeptide formation, glycine is used for the synthesis of heme
_______________ for
pyrimidines synthesis
aspartate and glutamine for
pyrimidines
_______________ for purine synthesis.
glycine, aspartic acid, glutamine and
serine for purine synthesis.
Some amino acids such as ________________, are used as detoxicants of specific substances.
Some amino acids such as glycine and cysteine, are used as detoxicants of specific substances.
Methionine acts as “active” _______________ transfers methyl group to various substances by transmethylation.
Methionine acts as “active” methionine (S-adenosylmethionine) transfers methyl group to various substances by transmethylation.
