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Oraby's Illustrated Reviews of For Medical Students And Postgraduates By M.B.B. Ch, M.S. (Clinical Pathology) M.S. & MD (Medical Biochemistry) Professor of. جميع كتب دكتور سعيد عرابي pdf لمادة biochemistry الجزاء الاول http://www. homeranking.info+Saeed+Oraby+Part+homeranking.info الجزاء. Find oraby biochemistry part 1 book in our library for free trial. We provide copy of oraby biochemistry part 1 in digital format, so the resources that you find are.
In certain conditions as during growth. Oraby's illustrated reviews of biochemistry 84 II. Urea formation. These enzymes catalyze what is called committed reactions of the pathway. Ornithine then undergoes transamination to give glutamate-y-semialdhyde which is converted to a-ketoglutarate as described for proline..
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Wikipedia in English None. Book description. Haiku summary. No library descriptions found. Quick Links Amazon. Amazon Kindle 0 editions. Audible 0 editions. CD Audiobook 0 editions. Project Gutenberg 0 editions. Google Books — Loading Local Book Search. In kidney. Ammonia intoxication: Will be discussed after the subject of urea It is also called Krebs' Henseleit cycle. The 6th one is N- acetylglutamate that acts as allosteric activator of carbamoyl phosphate synthase I. Arginine ': Then urea is transported by the blood to.
Plasma urea: The first two reactions occur in mitochondria where other reactions occur in cytosol. Six amino acids share in urea cycle: Protein metabolism 19 Vrea 1. Urea formation is the pathway through which the liver can convert toxic ammonia into non-toxic urea. Diagnostic importance of plasma urea determination: Liver is the only site for urea formation.
Formation of carbamoyl phosphate: Aspartate 1 F. Oraby's illustrated reviews of biochemistry 20 B. Carbon atom: Protein metabolism 21 N.
Carbon ammonia. Flow of nitrogen from ambto acid Formation of citrulline: Carbamoyl phosphate synthase II is a cytosolic enzyme used for pyrimidine synthesis.. This ammonia is partly lost in the feces and is partly reabsorbed into the blood.
The condition is called ammonia intoxication or hyperammonemia. A portion of the urea synthesized in the liver diffuses from the blood into the intestine and is cleaved into C02 and NH 3 by bacterial urease. Excess ammonia is toxic to the central nervous system. Regulation of urea cycle: Oraby's illustrated reviews of biochemistry 22 E. Oral administration of neomycin antibiotic reduces the number of intestinal bacteria responsible for the NH 3 production.
C02 needed for urea formation is mostly produced in TCA. It is activated allosterically by N-acetylglutamate. N-acetylglutamate synthesis is stimulated by high protein diet and amino acids especially arginine. Fumarate produced in urea cycle can be oxidized in TCA. Urea diffuses from the liver and is transported by the blood to the kidneys. Flapping tremors. This will promote urea cycle. Regulation of urea cycle. The key enzyme of urea cycle is carbamoyl phosphate synthase I.
Relationship between tricarboxylic acid cycle TCA and urea cycle: Fate of urea: Due to deficiency of arginino- suucinase. Protein metabolism 23 B. It results in what is called: Hyperammonemia type II. Liver cell failure: The diseased liver cells cannot convert ammonia into urea. Hyperammonemia type I. Inherited hyperammonemia: Due to deficiency of arginase. Renal failure. The most common inherited enzyme deficiency are: Collaterals between portal and systemic circulation due to cirrhosis of liver by bilharziasis.
Acquired hyperammonemia: Other enzyme deficiencies include: Due to deficiency of arginosuccinic acid synthase.
Types and causes of hyperammonemia: High concentration of ammonia may cause coma and death.. In cases of hyperammonemia..
Tyr Thr Val B Oraby's illustrated reviews of biochemistry 24 IV. At normal blood ammonia level. Mechanism of ammonia intoxication: Catabolised to form seven. This depletes a. These products enter different pathways which lead 1.
Asparagine is hydrolysed by the L-Aspartate enzyme asparaginase. Ketogenic and glycogenic amino acids: Amino acids can be classified as ketogenic or glycogenic according to the nature of their metabolic end products.
These are glutamine. Glycogenic or glucogenic amino acids are those whose catabolism gives pyruvate or one of the intermediate of citric acid cycle. Ketogenic and glycogenic amino acids are those whose catabolism gives either glycogen or lipid intermediates.: Aspartate loses its amino group by transamination to form oxaloacetate. F H20 A.. Protein metabolism 25 products: Amino acids forming a- Transaminase F Glutamate 0. These intermediates are substrates for gluconeogenesis and therefore can give rise to the formation of glycogen or glucose in liver and muscle.
Amino acids forming Asparaginase NH3 oxaloacetate: These are asparagine and aspartate. Glycogenic amino acids are sometimes named: Ketogenic amino acids are those whose catabolism gives either acetoacetate.
Synthesis of lipids. Synthesis of glycogen or glucose. Glutamate is then converted to a-ketoglutarate. Ornithine then undergoes transamination to give glutamate-y-semialdhyde which is converted to a-ketoglutarate as described for proline.. It is usually harmless. It is due to defective oxidation ofproline to glutamate. Hydrolysis of the latter gives N- formiminoglutamate FIGlu. It is useful test of folic acid deficiency.
Glutamine is converted to glutamate and ammonia by the enzymes glutaminase. Oraby's illustrated reviews of biochemistry 26 2. Serine can be converted to: Glutamate deamination. These are cysteine. N 10 methylene tetrahydrofolate or oxidized to CO:: Pyruvate 3. Amino acids forming pyruvate: These are alanine. Protein metabolism 27 Histidinemia: Amino acids forming acetvl CoA and acetoacetyl CoA: N10 methylene desulfuration to give pyruvate.
Amino acids forming fumarate: Glycine These are phenylalanine and tyrosine see metabolism of phenylalanine and tyrosine. I NH2 2. Orabyls illustrated reviews of biochemistry 28 b 5 amino acids form CHz IJ CoA: The major pathway for threonine catabolism in humans is its breakdown to glycine and acetaldehyde. L-Cysteine tyrosine. Sumnylpyruvic acid COOH directly acetoacetate Amino acids forming succinl!: These are methionine.. This results in synthesis of methionine.
It is metabolized to S-adenosyl methionine SAM. L-Methionine S-Adenosyl k H 0 2 tetrahydro-folate Me-H 4. Protein metabolism 29 F. L-Homocysteine i.. Methyl acceptors b Homocysteine has two fates: No clinical symptoms are present. This is an accumulation and excretion of cystathionine due to deficiency of cysta-thioninase enzyme. Leucine is pure ketogenic. Liver is deficient in transaminase required for their transamination.
All are essential amino acids and their catabolism is discussed as a group. The transamination of the branched chain amino acids occurs mainly in muscle. Catabolism of the branched chain amino acids: Isoleucine and valine will be discussed with catabolism of branched chain amino acids. This reaction is similar to that catalyzed by pyruvate dehydrogenase complex. All known 20 amino acids are very important to human. Maple surup urine disease: It is accumulation of a-ketoacids of branched chain amino acids and their excretion in urine.
They are classified nutritionally into essential amino acids.. Synthesis of alanine. Oraby's illustrated reviews of biochemistry 32 c Succinyl CoA. Glutamate is unusual in that it can also be synthesized by the reverse of oxidative deamination.
They are synthesized from the corresponding a-ketoacids: Synthesis of glycine. L-sertne VI. Synthesis of glutamine and asparagine: Glutamate is converted into proline by forming glutamate semi- aldehyde. Homocysteine is derived from methionine see methionine catabolism C. Serine is synthesized from 3 Phosphoglycerate a product of glycolysis as follows: Glycolysls--t - 3-Phospho-D-glycerate e: Glycine can be synthesized from serine by removal of a methylene group see serine catabolism.
Synthesis ofproline: Synthesis of tyrosine: Reduction of the latter gives proline see proline catabolism v. They are synthesized by amidation in reactions catalyzed by glutamine synthetase and asparagine synthetase.
Cystathionine is hydrolyzed to cysteine and homoserine. Cysteine is synthesized by 2 successive reactions: Homocysteine combines with serine to form cystathionine. Protein metabolism 33 III. Neurotransmitter Glyoxylic acid A.. Bile salts Glycine is non-essential glycogenic amino acid. Hippuric acid Purine bases: II 7 Carbon atoms NO. It is synthesized in two H Glutathione steps catalyzed by y-glutamyl cysteine synthetase and glutathione synthetase see amino acids absorption page s.
It is also called y-glutamyl. Heme hemoglobin 6. Creatine 4. Glycine is the precursor for: Glutathione 3. Serine amino acid 7-Collagen 8. Functions of creatine: Creatine N-methyl-guanidoacetate: It is a reducing substance: This occurs in muscles. It combines with them to produce non toxic compounds: This enzyme is present in liver.
This occurs by two reactions in kidney and liver.. Oraby's illustrated reviews of biochemistry 36 2. Synthesis of creatine: It is synthesized from three amino acids: Creatine kinase enzyme CK: Also called creatine phospho kinase CPK: Heme is the pigment.
It gives this carbon to glycine to form serine. These are sodium and potassium salts of glycocholic acid. Diagnostic importance of determination of plasma creatinine: Bile salts: Glyoxylic acid is formed from glycine by 2 mechanisms: Glyoxylic acid t. Glycine acts as an inhibitory transmitter in spinal cord and medulla.
All collagen types have a triple helical structure. This occurs in the liver. Hippuric acid: Glycine conjugates with the toxic compounds like benzoate an additive used to preserve foods to form the non-toxic hippuric acid.. Each helix is formed of 3 amino acids.
This leads to formation of urinary oxalate stones.: This condition usually ends by death in early life from either renal failure or hypertension. This leads to oxalate formation. Primary huperoxaluria: It is a metabolic disease characterized by excessive excretion of oxalate unrelated to dietary intake of oxalate. Protein metabolism 39 b Transamination: By reamination transamination.
Fate of glyoxylic acid: Catabolism of glycine: Tyrosine is the precursor for: Tyrosine is a ketogenic and glycogenic non. Deficiency of either phenylalanine hydroxylase or dihydrobiopterin reductase results in a disease called: Phenylalanine can be converted to tyrosine mainly in liver as follows: Phenylalanine is a ketogenic and glycogenic essential ca 1 -cn-coon amino acid.
Tyrosine becomes essential in case of deficiency of phenylalanine hydroxylase enzyme. This reaction needs phenylalanine hydroxylase enzyme and tetrahydrobiopterin as coenzyme. Asco1blc acid lrcHz-CH: Functions of catecholamines: Norepinephrine and dopamine act as neurotransmitters in the brain and at most sympathetic postganglionic endings.
Synthesis of catecholamines: They are synthesized from tyrosine at storage sites: These are dopamine. Protein metabolism 41 A. These metabolites undergo: Oraby's illustrated reviews of biochemistry 42 b In adrenal medulla: It is present mainly in the mitochondria of adrenergic nerve endings. They can be used as index of the rate of catecholamines secretion.
Are methylated by COMT to metanephrine and normetanephrine. It is inhibited by feed back inhibition by either dopamine or nor epinephrine.. This enzyme catalyzes the conversion of norepinephrine to epinephrine [by transmethylation]. Tyrosine hydroxylase is the key enzyme. Synthesis of melanins: In the skin..
Melanin pigments: T hyroid hormon es: Fu n c tion s of thyroid hormones: The two major hormones produced by thyroid gland a rc th y ro x in T 1 and triiodothyronine T3. T1 r'f1 J tripeptide ho r mone produced Structure of tnvrold homloii8S and related in the hypothalamus. J T 4 arc stimulated by thyroid st imul a tin g h ormone TSH.
Oraby's illustrated revtews of biochemistry 44 Functions of melanin: I growth hormone. Thyroid system c. Triiodothyronine [T: Dllodotyroalne DIT ' Reverse triiodothyronine [rT 3 ]. This needs H: Protein metabolism 45 e Steps of thyroid hormones synthesis: Tetraiodothyronine [thyroxin Free T3 and T.
Plasma T: The carbon skeletons that have left after the removal of amino groups of both phenylalanine and tyrosine may catabolize to form fumarate glycogenic or acetoacetate ketogenic.
T4 and TSH must be done for every newly born infant in the first few days after birth as screening test of cretinism. Cretin e If the disease occurs later in life. Oraby's illustrated reviews of biochemistry It results from deficiency of dihydrobiopterin reductase enzyme. I melanin t! Inborn errors of phenylalanine and tyrosine metabolism: Phenylalanine is converted to phenylpyruvate and phenyllactate.
Effects signs and symptoms: COOH I! It is inherited deficiency of phenylalanine hydroxylase enzyme. It is inability to metabolise tyrosine and p-hydroxy phenyl pyruvate. Hereditary tyrosinemia tyrosinosis: Death from liver failure occurs within 7 months. Normally it is between The cause of mental retardation is unknown.
Pyruvate is 1 I precursor of tricarboxylic acid cycle that gives energy in brain. Frequency of phenylketonuria: For unknown cause methionine. There is also a mild mental retardation. Liver cirrhosis and hepatic carcinoma are common. Abnormal high phenylalanine level will be found in cases of phenylketonuria. Ketoglutarate 05lno u. Kotoglutarato franoamlnuo Transamination Glutaate.: Intermediate steps Kaleylacetoacetate. It is a hereditary deficiency of tyrosine hydroxylase enzyme in melanocytes.
This results in defective synthesis of melanin pigments. Types of albinism: It is a benign disease resulting from deficiency of homogentisate oxidase enzyme.
Homogentisate increases and causes: Protein metabolism 49 C. Functions of serotonin: The product s-hydroxytryptophan is decarboxylated to serotonin.. It is glycogenic and ketogenic essential amino acid. L N-acetylserotonin. Tryptophan is the precursor of: Storage sites of secretion: Serotonin also called s-hydroxytryptamine.
The resulting compound.. This causes increase of serotonin. Oraby's illustrated reviews of biochemistry 50 q'ryptophan Protein metabolism 51 transmitter in brain.. Functions of melatonin: These drugs are used in treatment of psychic conditions as depression..
Hydroxy lndol acetic acid. Thus symptoms and signs of pellagra developed. Site of secretion: These are diarrhea. This is because it inhibits the flow of free fatty acids FFA from adipose tissue. Niacin nicotinic acid: Synthesis of melatonin. NJI b Melatonin is secreted H only at night dark. Synthesis of melatonin: Oraby's Illustrated reviews of biochemistry 52 3. Functions of niacin: Niacin is a member of vitamin B complex.
Synthesis of niacin: ONby c. These are. OH n2 3. Indole and skatole: Oraby's illustrated reviews of biochemistry 54 Hartnup 's disease: Glutathione synthesis: This is a tripeptide forming of three amino acids: Para-amino benzoic acid PABA. Glutamic acid is a nonessential glycogenic amino acid. Remoyal of amino group of most amino acids in the form of ammonia through transdeamination see deamination of amino acids B.
Folic acid synthesis: Functions of glutamic acid: Folic acid is a member of vitamin 8-complex being composed of pteridine base. Glutamine synthesis: Glutamine is synthesized from glutama'te in the reaction catalyzed by glutamine synthetase for functions of glutamine.
Enzyme activator: N-Acetylglutamate activates carbamoyl phosphate synthase enzyme see urea biosynthesis. GABA is pre-synaptic inhibitory transmitter.. L-glutamate decarboxylase or pyridoxal phosphate. Gamma aminobutyric acid GABA: Functions of GABA: It is an inhibitory transmitter in brain and spinal cord. Jlspartate I. Synthesis of GABA: It is synthesized from L-glutamate by L-glutamate decarboxylase in the presence of pyridoxal phosphate as coenzyme.
Folic acid acts as a carrier of one carbon units.
Catabolism of GABA: It is metabolized within the neurons to succinate: Protein metabolism 55 Glutamate acts as excitatory neurotransmitter in all CNS neurons It is non-essential glycogenic amino acid. GABA is a postsynaptic inhibitory transmitter.. Functions of aspartate: Urea formation: Aspartate reacts arginosuccinate.
In bacteria. Asparagine formation: Pyrimidine 1. Synthesis and breakdown: Orsby's illustrated reviews of biochemistry 56 II. Pyrimidine formation: Aspartate is the source of N" C. Purine formation: Aspartate coo JJ. In mammalian tissues p alanine arises during catabolism of cytosine base.
Creatine formation: NO is an Acetylc: I hydrobiopterin " 2. Functions of arginine: Arginine I. Nitric oxide: L-Arginine serves as a precursor of nitric oxide NO. Protein metabolism 57 2. Arginine phosphate arginine. Nitroglycerine glyceryl trinitrate is a powerful coronary vasodilator through increasing NO formation. It is glycogenic.. NH2 Putrescine.
Ornithine is important for: This maintains the action of cGMP as smooth muscle relaxant and vasodilator and used as a drug that maintains penile erection It is a glycogenic. Ornitliine I. A Omltttln decalboxytase See the figure. Urea formation. Spermidine and spermine formation: These are polyamines formed in prostate by ornithine and methionine.
Ornithine 2. CH2 3. CH2 NH2 Spermine. Oraby's illustrated reviews of biochemistry 58 3. I - Ocooa B Proline Hydroxy proline Hydroxyproline synthesis: Spermine a Spermine is spermidine and putrescine. Functions of proline: Collagen synthesis: Proline and hydroxyproline are very rich in collagen. These are non-essential glycogenic imino acids. Ascorbic acid deficiency leads to a weak collagen scurvy. Catabolism ofproline: Cysteine Cystine Cysteine Methionine I.
Discussed in glycine metabolism. Its sodium salt sodium taurocholate is one of bile salts. This is a component of fatty acid synthase enzyme.
It enters in the synthesis of: Oraby's illustrated reviews of biochemistry 60 Sulfur containing amino acids.. It combines with cholic acid to form taurocholic acid. It is a coenzyme. A part of the vitamin: Pantothenic acid. Cysteine is glycogenic. Taurine c. Cysteine sulfinic acid Cysteic acid Cysteine is important for the detoxication of some aromatic com ounds e. Protein metabolism 61 D.. This build-up may lead to a heart attack. Cystine di-cysteine is glycogenic. Cystine may precipitated in renal tubules forming renal stones Cysteine formation: Homocysteine A homocysteine test measures the amount of the llJil.
Protein synthesis: Cysteine is very important amino acid for some proteins as: Protein structure: Homocysteine may get high levels when cholesterol Keratins are very rich in cysteine..
Many enzymes: It has the.. Histamine is derived from histidine by decarboxylation. Histidine 1. S-Adenosylmethionine SAM: The main methyl donor.. Ergothionine following functions: Methionine is glycogenic. It is essential. Jfistidine I. Spermidine and spermine: These are large amounts of histamine in the hypothalamus and in anterior and posterior lobes of the pituitary gland.
Cysteine synthesis: Through formation of homocysteine. Aromatic L-amino acid '.. Histamine reactions or trauma. Histamine is secreted by Functions: Lipotropic factor: Methionine is one of lipotropic factors..
This reaction is catalyzed by either 2 different enzymes: It is used for synthesis of: NHz A. Serine I. Anserine is produced by methylation of carnosine. It is a dipeptide composed of the amino acid derivative. It "'Glycine enters in the structure of sphingomyelin see "' Ethanolamine and choline lipid metabolism part II.
It is N-trimethyl. Carnosine and Anserine: The -OH group of Serine serine residues present in proteins is the site Functlcms: Carnosine is a substance results from conjugation of histidine with P-alanine. Both are present in skeletal muscles and not in cardiac muscle. Caraoelae D. Protein metabolism 63 B. Serine is used for the synthesis of: It is present in brain at levels times higher than carnosine levels. Sphingosine base: Serine reacts with "'Cysteine "' Purine bases palmityl CoA to form sphingosine base.
Serine reacts with homocysteine derived from S- adenosyl methionine to form cysteine see methionine catabolism. Serine is non-essential. Through the action of threonine aldolase enzyme. These are non-essential. Threonine is usedfor the synthesis of: Oraby's illustrated reviews of biochemistry 64 D. P-Alanine is important for the synthesis of: NH 2 fi -Alanine lll. Like serine. Alanine is the main amino acid that is converted 8 into glucose in liver through alanine-glucose cycle.
Through the action of serine hydroxy methyl transferase. COOH C. COOH A. Alanine is a major component of bacterial cell wall. Alanine -together with glycine. Alanine B. Ethanolamine and choline: Carnitine acts as a carrier. This process is called protein turnover. Valine is glycogenic. This is to provide body needs of proteins. J'rotein turnover 1. Thus the total amount of protein in the body remains consltlnt. Lysine and hydroxylysine arc very rich in collagen.
Hydroxylysine synthesis: It is synthesized from lysine.. Most proteins in the body.. CH 3 CH 3 membrane. This is essential for fatty acid oxidation Carnitine see lipid metabolism. In certain conditions as during growth. COOH I 2. All are essential amino acids. Carnitine synthesis: It is!
Lysine is an essential In healthy adult.. In adult: This leads to hypoproteinemia with subsequent edema. In urine: Urea main solute gfday Uric acid o. It occurs in conditions where the formation of tissue proteins is increased e.
In feces: One gram I day is excreted in feces. Nitrogen intake: Nitrogen is taken in the form of dietary proteins. Nitrogen loss: Nitrogen is lost from the body through non- protein nitrogenous NPN compounds: It occurs in conditions where breakdown of tissue proteins is increased e. This condition is due to dietary deficiency of proteins. Hypoproteinosis A. Positive and negative nitrogen balance: Nitrogen balance means that nitrogen intake is equal to nitrogen loss from the body.
Negative nitrogen balance: It means that nitrogen intake is less than nitrogen loss. Every gm protein contain 16 gm nitrogen: Positive nitrogen balance: It means that nitrogen intake is greater than nitrogen loss. It ends with death. Alzheimer's disease:. Removal of amino group from amino acids by deamination. Synthesis of urea from ammonia.