PROTEINS Flashcards
df STRUCTURE OF AMINO ACIDS AND
PROTEINS , CLASSIFICAION ,
-Proteins are the necessary components of all living organisms,
they are involved in most of the vital processes of the cell
-classifications based on the biological role of amino acids,
1. According to the structure of the compounds formed by the
breakdown of amino acids, distinguish:
a) glucogenic amino acids, which, when broken down, turn into
one of five metabolites capable of participating in gluconeogenesis
(2-oxoglutarate, succinyl-COA, fumarate, oxaloacetate and
pyruvate). This occurs when there is an insufficient intake of
carbohydrates or a violation of their transformation. This group
includes glycine, alanine, serine, threonine, valine, aspartic and
glutamic acids, arginine, histidine and methionine;
b) ketogenic amino acids that accelerate the formation of
ketone bodies. They include lysine, leucine, isoleucine, tyrosine and
phenylalanine (the last three can be glucogenic).
2. Depending on whether amino acids can be synthesized in the
body or not, it is possible to distinguish:a) non-essential; b) essential (histidine, leucine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine. In childhood, arginine is also an essential acid).
—structure :
1) the primary structure is a sequence of amino acid residues in a
protein bound by a peptide bond ,The presence of disulfide
bonds between two cysteine residues in one polypeptide chain with
the formation of cystine or different polypeptide chains in a protein
molecule is possible;
2) the secondary structure characterizes the shape of the protein
chain in space. This form varies depending on the set of amino acids
and their sequence in the polypeptide chain. There are two main
options of secondary structure: α-helix and β-configuration (β-
pleated sheet):
a) the form of α-helix is found in many proteins. This is
the correct spiral around the imaginary cylinder. The stability of the
spiral configuration is determined by numerous hydrogen bonds
between CO- and N-groups of peptide chains.
b) β-configuration is characteristic of a small number of proteins
in the molecule of which there is more than one polypeptide chain.
The shape of this structure can be compared with the bellows of the
accordion (folded structure).
Along with hydrogen, both forms of the secondary structure
have other bonds:
- electrostatic, which occur between two oppositely charged
polar groups. These bonds are stronger than hydrogen;- hydrophobic, which occur between non-polar water-insoluble groups. These radicals are converging due to their expulsion from the water;
3) the tertiary structure occurs due to the curvatures of the
polypeptide chain . This configuration can be represented as a
spiral formed on the cylinder, the axis of which periodically changes
direction, which leads to the formation of a tangle. In this structure,
hydrophilic groups are located on the surface of molecules, and
hydrophobic groups are close to each other in its internal regions.
They play an important role in maintaining the tertiary structure. The
hydrophobic, hydrogen and electrostatic interactions are involved
also in the maintaining of the tertiary structure stability;
4) the quaternary structure is formed as a result of the
connection of subunits in a complex formation (fig.2). Subunits are
connected by weak bonds, which are easily dissociated. The classic
examples of a molecule with a quaternary structure are the enzyme
lactate dehydrogenase, phosphorylase A, hemoglobin, tobacco
mosaic virus envelope protein.
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-CLASSIFICATION OF PROTEINS :
I. Simple:
a) globular:
- albumins
- globulins
- protamins
- histones
b) fibrillar:
- collagen
- elastin
- keratin
II. Complex:
1) glycoproteins;
2) lipoproteins;
3) chromoproteins;
4) phosphoproteins;
5) metalloproteins;
6) nucleoproteins.
FUNCTIONS OF PROTEINS
- Catalytic
- Transport
- Protective
- Contractile
- Structural
- Hormonal
- Energy
- Colloid osmotic
METABOLISM OF PROTEINS
METABOLISM OF PROTEINS
Daily requirement :
1-hard physical act : 1.2g/kg
2-modorate physical act : 1.0/kg
3-sadentry physical act : 0,8 g/kg
Enzymes of gastric juice:
- pepsin
- gastrixin
- rinin
Enzymes of pancreatic juice:
- trypsin
- chymotrypsin
- carboxypeptidase
- elastase
Intestinal wall enzymes:
- aminopeptidase
- dipeptidase
Ways of using amino acids in the body.
Ways of using amino acids in the body.
1. Protein synthesis.
2. The formation of hormones,
neurotransmitters.
3. Cleavage with formation of
carbohydrates, lipids, ketone bodies, etc
Neutralizing ammonia in the body
- In the human body, about 70 g of amino acids are broken
down every day. - A large amount of ammonia is released (a highly toxic
compound). - The concentration of ammonia in the body should be kept at a
low level. - It is achieved by binding ammonia and removing it from the
body. - The most important way of ammonia neutralization is
urea cycle (also known as the ornithine cycle)
explain the UREA
- Urea is synthesized in the liver in the ornithine
cycle. - Urea is excreted from the body mainly through the
kidneys by filtering in the glomeruli. - Urea can be excreted from the body also
extrarenally. Through sweat and feces excreted less
than 10% of the total concentration of urea in the
plasma. - The state when the concentration of urea in the
blood is several times higher than normal is called
uremia
——–
-Causes of increased blood urea levels: - I. Suprarenal
1) rich protein diet;
2) high protein catabolism in fevers, heavy muscle work;
3) blood loss; reduction of filtration
4) acute dehydration; leukemia;
5) a serious infectious disease;
6) burns; shock.
II. Renal (kidney disease, accompanied by a decrease in
glomerular filtration and loss of nephrons).
III. The subrenal
1) obstruction of the urinary tract;
2) adenoma of the prostate;
3) tumors of the urinary system.
—————–
-Reasons for the decrease in the level of
urea in blood:
1) congenital failure of urea synthesis;
2) severe liver failure
explain the URIC ACID , df , types
- Uric acid is the final product of the
purine nucleotides (adenine,
guanine) exchange. - The bulk of uric acid is produced by
the liver. - Uric acid is poorly soluble in water
and crystals of its salts – urates,
deposited in the joints and urinary
tract, cause the development of
gout and the formation of uric
stones in the kidneys. - Uric acid excreted by kidneys and
extrarenally ( with sweat and feces).
—-
-types :
1-Primary uricemia
1) defect of the enzyme hypoxanthinguanine-phosphoribosyl-transferase
(Lesch-Nyhan syndrome: self-harm, aggressiveness cognitive disturbances, choreoathetosis, kidney failure.)
2) increasing the activity of the enzyme phosphoribosyl- pyrophosphate-synthetase, which stimulates the destruction of purine metabolism products to uric acid;
3) reduced tissue sensitivity to elevated uric acid concentration (loss of feedback);
4) insufficiency of protein in blood plasma that transports uric acid;
5) congenital functional features of the kidneys
2-Secondary uricemia - 1) eating food containing large amounts of purines (red meat,
liver, fish, caviar, cheese, alcohol) → GOUT “disease of kings” ; - 2) fasting (destruction of tissues);
- 3) hematological diseases;
- 4) leukocytosis, erythrocytosis;
- 5) renal failure;
- 6) epilepsy;
- 7) glycogen storage disease type I;
- 8) dehydration;
- 9) diabetes mellitus type II;
- 10) hypertension;
- 11) malignant neoplasms;
- ## 12) psoriasis.-Reasons for lowering uric acid levels in the blood:
1) defect of xanthine oxidase enzyme, resulting in the
final product of purine metabolism is not uric acid, but xanthine;
2) reduction of tubular reabsorption;
3) pulmonary tuberculosis, especially in the acute stage
(damage of the tissues ability to retain uric acid)
CREATINE AND CREATININE , df , synthesis, Causes of increase/decrease
- Creatinine is formed in the body from creatine.
- Creatine synthesis occurs in two stages. The first stage is
carried out in the kidneys, where the precursor of creatine is
formed from arginine and glycine. The final formation of
creatine is completed in the liver. - The creatine through the blood directed to the muscles, which
produce a creatine phosphate . - With muscle contraction, creatine phosphate is destroyed with
the formation of ATP and creatinine. - ## Creatinine is then excreted by kidneys-Causes of increased creatine in the blood:
- CHILDREN, TEENAGERS
- PROTEIN DIET
- SKELETAL MUSCLE DISEASES
- ENDOCRINE DISEASES
- LEUKOSIS
- LIVER DISEASES
- RHEUMATOID ARTHRITIS
- BURNS
-Causes of increased creatine in the blood: - ACROMEGALY
- DIABETES
- KIDNEY FILTRATION DISTURBANCE
- EXERCISE STRESS
- CRASH SYNDROME
- RADIATION SICKNESS
explain INDICAN , df , formation , Causes of increase
-INDICAN (0,87-3,13 МКМОЛЬ/Л)
* Indican is formed in the liver from indole, which, in turn, is
formed by bacterial rotting of proteins in the intestine.
* The decomposition of the amino acid tryptophan in the
intestine leads to the formation of a toxic substance indole.
* Indole through the portal system enters the liver and is
inactivated by binding in the liver with sulfuric or glucuronic acid.
* The resulting indican is non-toxic and excreted through the
kidneys by filtration
————–
-Causes of increased concentration of indican in the blood:
1) Functional renal failure (reducing of urine excretion).
2) Extra-intestinal formation of indole in autolysis of tissue protein and its bacterial decay (purulent appendicitis, lung abscess).
3) Strengthening of putrefactive processes in the intestine, stagnation of intestinal contents (prolonged constipation and intestinal obstruction)
PROTEINS OF BLOOD PLASMA ,TOTAL PROTEIN ,Causes of hyperproteinemia ,Protein fractions of blood plasma ,
- IN CLINICAL DIAGNOSTIC LABORATORIES WE DETERMINE THE QUANTITY OF:
1) TOTAL PROTEIN
2) PROTEIN FRACTIONS
3) INDIVIDUAL PROTEINS
-TOTAL PROTEIN - The level of protein in the blood is normal:
- in adults – 60 – 85 g / l.
- in newborns-47-65 g/ l;
- at the age of 1 month-41-55 g / l;
- 1 year-57-78 g / l;
- 1-4 years-59-79 g / l;
- ## 5-14 years-62-82 g/l;-Causes of hyperproteinemia
(↑ total protein in blood)
1) acute and chronic infections;
2) autoimmune diseases;
3) paraproteinemic hemoblastosis (multiple myeloma);
4) sarcoidosis;
5) dehydration
-Causes of hypoproteinemia (↓ total protein in blood)
I. Reduction of protein synthesis: poor nutrition; intestine disease
(malabsorption); liver disease.
II. Increased protein loss by the body (nephrotic syndrome; ascites, exudates, transudates; burns; bleeding)
III. Increased protein breakdown in the body (thyrotoxicosis; fever; injuries; tumors)
IV. Over-hydration (relative hypoproteinemia)
-Protein fractions of blood plasma:
1) albumins (55-65%)
2) α1-globulins (2-5%)
3) α2-globulins (7-13%)
4) β-globulins (8-15%)
5) γ-globulins (12-22%)
explain α1-globulins ,α2-globulins ,β-globulins,γ - globulins
1-α1-globulins
-The reasons for the increase:
1) acute inflammation;
2) exacerbations of chronic diseases;
3) allergic diseases;
4) burns;
5) injuries;
6) autoimmune diseases;
7) malignant neoplasms.
-Individual proteins :
α1-fetoprotein
α1-antitrypsin
prothrombin
transcortin
thyroxin-binding globulin
retinol-binding globulin
transcobalamin
——————–
2- α2-globulins
-The reasons for the increase:
1) acute inflammation;
2) exacerbations of chronicdiseases;
3) allergic diseases;
4) burns;
5) injuries;
6) autoimmune diseases;
7) malignant neoplasms
Individual proteins :
ceruloplasmin
haptoglobin
antithrombin III
antithrombin IV
C1 and C9 complement
components
α2-globulin that binds uric acid
plasminogen
erythropoietin
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3-β-globulins
The reasons for the increase:
1) chronic inflammation;
2) cholestasis;
3) hyperlipoproteinemia;
4) nephrotic syndrome;
5) diabetes mellitus;
6) hypothyroidism;
-Individual proteins :
a) β - lipoproteins;
b) transferrin
d) C2-C8 complement components;
d) fibrinogen;
e) C-reactive protein (CRP)
———————-
4- γ - globulins
The reasons for the increase:
1) chronic inflammation;
2) autoimmune diseases;
3) allergic diseases;
4) parasitic diseases;
5) paraproteinemic hemoblastosis.
-Individual proteins :
Ig G
Ig M
Ig E
Ig A
Ig D
protein analysis
1-
-tottal protein : 60-85 norm
-a1 : up , a2 up , + C reaction
= Acute inflammation
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2-
-tottal protein : 60-85 norm
-b : up , Y up , - C reaction
= chronic inflammation
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3–tottal protein : above 85
-b : up , Y up ,
=hepatic type
———————–
4-
tottal protein : above
-M spike or M gradiant apear more then 50%
=Para proteinemia
———————–
5-
-tottal protein : down
-b : up , Y up , - C reaction = chronic type
-a1 : up , a2 up , + C reaction = acute type
= nephrotic type
———-
6-
-tottal proteins : down
- sharp decrease in one of the fracture
-the rest norm or increase
=protein synthesis deficiency
