Biochemistry Globular Proteins Team 434 Respiratory Block Color index: Red= Important Purple= Addition Orange= Explanation [email protected] ❖ ● What are globular proteins? ● Types and functions of globular proteins ● Hemoglobin (a major globular protein) ● Myoglobin ● a, b-globulins ● g-globulins (immunoglobulins) ● Diseases associated with globular proteins YOU CAN FIND THEM IN In Bone matrix and Muscle fibers. ❖ Examples: It gives myoglobin and hemoglobin the ability to bind oxygen because of the presence of iron atom. NOTE: dimer is α and β NOT β & β OR α & α. It also contributes to the red color found in muscles and blood so what’s a Heme Group? ❖ Hemoglobin function: Carries oxygen from the lungs to tissues and carries carbon Demonstration dioxide from tissues back to the lungs. Normal level (g/dL): ● Males: 14-16 ● Females: 13-15 Extra Info:The unliganded (deoxy) form is called the "T" (for "tense or tight") Remember by this : state has low- affinity for O2 because it contains extra stabilizing interactions ● Tense in Tissue. between the subunits. In the high-affinity “R”(for”relaxed”)state conformation the ● Relaxed in Respiratory interactions which oppose oxygen binding and stabilize the tetramer are somewhat weaker or "relaxed". tract. ❖ Normal Hb Abnormal Hb Unable to transport O2 due to it’s abnormal structure HbA(97%) HbA2(2%) HbF(1%) HbA1c Carboxy-Hb Met-Hb Sulf-Hb HbA appears Major hemoglobin nHbA undergoes structure about 12 found in the fetus non-enzymatic is the weeks Reversible. Irreversible. and newborn and glycosylation Reversible. Oxygen after its function is becomes normal by spontaneously vit.c binding to birth. unknown in adults. depending on hemoglobi composed Forms due to Tetramer with 2 plasma glucose CO replaces When Fa++ n AND it α high sulfur of 2 ,2 δ α and 2 γ chains. levels. O2 and (Ferrous) levels in is found globin binds 200X becomes Fe+++ since it has high in patients blood adults. chains. tighter than (Ferric) ~2% Higher affinity with diabetes O (in 2 that cannot for O2 than HbA, mellitus. smokers). O2 is carry O2. Transferred from HbA+glucose=Hb1c get degraded by maternal to fetal sensitive and enzymes so it’s circulation across specific marker enzyme related placenta. for sugar level in blood ❖ caused by 1. • Synthesis of structurally abnormal Hb ( qualitative). 2. • Synthesis of insufficient quantities of normal Hb ( quantitative). 3. • Combination of both. ❖ ❖ what is it ? Structure Function Types Defensive proteins Y-shaped structure Neutralize bacteria IgA, IgD, IgE, IgG, IgM produced by the B- with 2 heavy and 2 and viruses cells of the immune light polypeptide system chains ❖ Globular Proteins Y-globulins Hemoglobin Myoglobins a1,a2,B-globulins Enzymes (Immunoglobulins) Normal Abnormal HbA: Found in adults. Carboxy Hb: CO2 replaces O2. HbA2: Found in adults in little amounts. Met Hb: Oxidized Fe+++. HbF: In fetus. Sulf Hb: Sulfur binding with O2. Hemoglobinopathies: - Methemoglobinemia: Oxidation of Hb to Ferric. (Chocolate Cyanosis) - Sickle cell disease (HbS): Glutamic acid replaced by Valine → Sickle cell anemia. - Hemoglobin C disease: Glutamic acid replaced by lysine → Mild hemolytic anemia. - Thalassemia: alpha-thalassemia (mild & moderate) OR beta-thalassemia (severe). Myoglobinuria: Specific marker for muscle injury. ❖ 2-Which of the following is the major type of 1-Which of the following is a globular protein? normal Hb? A- Actin B- Myosin A- HbA B- HbA2 C- Hemoglobin D- All of the above C- HbF D- HbA1c 3-Which of the following is irreversible? 4-In Met Hb the iron is in the form of …? A- Carboxy Hb B- Met Hb A- Ferris B- Ferric C- Sulf Hb D- Non of the above C- Both of them D- Non of the above 5-Which of the following is true about HbA structure? 6-What is the form in which majority Carbon dioxide is transported in the A- Weak ionic and hydrogen bonds between ab dimer pairs blood ? B- Strong interactions between a and b chains from stable ab A- Bicarbonate B- Carbon Monoxide dimer C- Both A & B D- Non of the above C- Strong ionic and hydrogen bonds between ab dimer pairs D- Weak interactions between a and b chains from stable ab dimer 7-Which of the following is the major 8-When does HbA2 appears? hemoglobin found in the fetus and newborn? A- 10 weeks after birth B- 12 week after A- HbA B- HbA2 birth C- HbF D- HbA1c C- 20 weeks after birth D- 22 weeks after birth 9-Which of the following Hb doesn’t require enzyme? 10-HbA1c levels are high in patients with ? A- HbA B- HbA2 A- Kidney disease B- Heart disease C- HbF D- HbA1c C- Diabetes mellitus D- All of the above 11-Methemoglobinemia can 12-Which of the following is true about myoglobin? bind oxygen A- T A- The non-charged amino acids are located on the surface B- F B- The heme group is present at the periphery of the molecule C- Myoglobin gives red color to skeletal muscles D- Supplies oxygen during anaerobic exercise ❖ ● Hemoglobin and Hemoglobinopathies ● Oxygen Transport ● DIFFERENT TYPES OF HEMOGLOBIN ❖ ● Nouf AlOraini ● Rana AlJunadil ● Reema AlRasheed ● Sheikhah AlDosari ● Jumana fatani ● Maha AlRabiah .