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.
______________ are sources of sulfur.
Cystine and methionine are sources of sulfur.
________________________ - Found in collagen of connective tissue
Hydroxyproline and hydroxylysine - Found in collagen of connective tissue
_________________ -Found in myosin, a muscle protein functioning in contraction.
N-Methyllysine -Found in myosin, a muscle protein functioning in contraction.
__________________ - Found in the blood-
clotting protein prothrombin.
Gamma-carboxyglutamic acid - Found in the blood- clotting protein prothrombin.
__________ - A derivative of lysine, found only in the fibrous protein elastin
Desmosine - A derivative of lysine, found only in the fibrous protein elastin
________________ : not synthesized by the body and must be taken in the diet
Essential Amino Acids
____________________ : These can be synthesized by the body and may not be
the requisite components of the diet.
Non-essential amino acids: These can be synthesized by the body and may not be
the requisite components of the diet.
_____________________ : These are growth promoting factors since they are not synthesized insufficient quantity during growth. They include ___________________ (for infants only and not for adult). They become essential in growing children, pregnancy, and lactating women.
Semi-essential amino acids: These are growth promoting factors since they are not synthesized insufficient quantity during growth. They include arginine and
histidine (for infants only and not for adult). They become essential in growing
children, pregnancy, and lactating women.
_________________ : are usually not essential, except in times of illness and
stress.
Conditional amino acids
10 essential amino acid:
PVT TIM HALL
Conditionally Non-Essential Amino acid:
Arginine
Asparagine
Glutamine
Glycine
Proline
Serine
Tyrosine
Non-Essential Amino Acid:
Alanine
Asparatate
Cysteine
Glutamate
The configuration of alpha-amino acids isolated from proteins is in ____________, in which the amino group attach in alpha carbon is on the left side.
The configuration of alpha-amino acids isolated from proteins is in L configuration, in which the amino group attach in alpha carbon is on the left side.
- When an alpha amino acid is boiled with
it , a powerful oxidizing agent forming a
purple product (ruhemann’s purple) - Proline and hydroxyproline will give a yellow color
- Use as quantitative and qualitative test for protein
Ninhydrin Reaction
________________ is 1-fluoro-2,4-dinitrobenzene (FDNM).
- It is useful in the identification of individual amino acids.
- Gives colored bright yellow
- Important in determining the amino acid sequence of peptides.
Sanger’s reagent
The ____________ is an amide
bond formed between the -COO-
group of one amino acid and a-
N+H3 group of another amino
acids.
peptide bond
The molecules formed by
condensing 2 amino acids is
called __________. The amino acid
free a-N+H3 group is know as N-
terminal amino acid (amino
terminal), and the amino acid
with -COO- group is carboxyl, or
C-terminal amino acid.
dipeptide
- a hormone secreted by B cells of
pancreas which stimulates the capacity of cells to use glucose as a metabolic fuel.
Insulin
- A hormone with 9 amino acid residue
secreted by the posterior pituitary gland which stimulates urine contraction
Oxytocin
- A substance that inhibits
inflammation of tissues
Bradykin
- a short peptide formed in the central nervous system; it binds to specific receptors in certain cells of the brain and induces analgesia, deadening of pain sensations.
Enkephalins
- A hormone of the pituitary gland stimulates the adrenal cortex.
Corticotropin
Protein which upon hydrolysis yield only amino acids or their
derivatives.
Simple Protein
They are composed of simple proteins combined with some non protein substance. The non-protein group is
referred to as the prosthetic group.
Conjugated protein
These proteins includes the artificially
synthesized protein-like compounds and those resulting from decomposition of proteins.
Derived proteins
Those proteins derivatives are formed by a
process which causes only slight changes in the protein molecule and its properties. There is no hydrolytic cleavage of peptide bonds. They are synonymous with denatured proteins.
Primary Derived Protein
- they are insoluble products formed by the incipient action of water, very dilute acids and enzymes
Proteins
- Formed by further actions of
acids and alkalies upon proteins.
Metaproteins
- They are insoluble products formed by the action of heat or alcohol upon natural protein
Coagulate proteins
They are formed in the progressive hydrolytic cleavage of the peptide union of protein molecules.
Secondary derived proteins
- they are hydrolytic products of
protein which are soluble in water, not
coagulated by heat.
Proteases
- a product of further hydrolytic
decompositions. They are simpler structure
than the proteases.
Peptones
- a compound of 2 or more amino
acids, either synthesized or resulting from the hydrolysis of proteins
Peptides
Peptide chain is tightly folded into
compact, spherical or globular shape.
- Usually soluble in aqueous systems and
diffuse readily.
- Nearly all enzymes are globular proteins,
as are blood transport proteins, antibodies and nutrient storage proteins
Globular protein
- Consist of polypeptide chains arranged
in a parallel fashion along a single axis,
to yield long fibers or sheets. - Physically tough and are soluble in
water or dilute salt solutions. - The basic structural elements
connective tissue of higher animals.
Ex: Keratin of hair, skin and nails
Fibrous proteins
- soluble in water, coagulated by heat; deficient in glycine. Ex: lactoalbumin, ovalbumin.
Albumin
- insoluble in water, coagulated by heat; contain glycine. Ex. Ovoglubulin, serum globulin
Globulins
- soluble in diluted acids and alkali, insoluble in neutral solvents; coagulated by heat. Ex: Glutamine of
wheat, oryzenin of rice
Glutelins
high content of amino acids, they
appear to occur in the combination with the nucleic acid in the nuclei of some somatic cells of organisms. Ex: Histones and globin
Histones
They are the simplest of the
proteins and may be regarded as large
polypeptides. They are strongly basic and yield chiefly basic amino acids upon hydrolysis, such as arginine. Ex: Salmine of salmon sperm
Protamines
least soluble of all proteins. Entirely animal proteins and are the chief constituents of exoskeletal structures which makes a supportive tissues.
Ex: Keratin and Collagen. Gelatin is a degenerated albuminoid
Scleroproteins of Albuminoids
- soluble proteins; plant
proteins found principally in seeds.
Ex: zein in corn, gliadin of wheat.
Prolamines of gliadins
- The prosthetic group is a nucleic acid. It is the protein of nuclei and apparently are the chief constituent of chromatin. Ex.
Nucleohistone
Nucleoproteins
The prosthetic group is phosphoric
acid. Ex: Casein
Phosphoteins
- composed of simple united with colored prosthetic group which is believed to be pigment. Ex: Heme of hemoglobin
Chromoproteins
- simple conjugated to lipids such as phospholipids and cholesterol.
Lipoproteins
- proteins plus metallic elements such as Fe, Cu, Mn.
Ex: Copper of ceruloplasmin
Metalloproteins
amino acid that can be converted to ketone
ketogenesis
amino acid that can be converted to ketone
ketogenic
the only optically inactive amino acid
glycine
What is the name of the only amino acid in which R group is connected to N terminal of amino acid?
proline
