Clinical Enzymes: Functions and Applications OmpathStudy

... 1. Acid Phosphatase Basic Function Primary Role : Hydrolysis of phosphate esters at acidic pH (5-6) Location : Lysosomes (cytoplasmic enzyme) Distribution : Prostate gland, liver, spleen, RBC, platelets Clinical Applications Prostate Cancer Screening : Primary diagnostic tool for prostate carcinoma in males <35 years Forensic Medicine : Confirmatory test for sexual assault cases Cancer Detection : Identifies ectopic sources in breast cancer and other malignancies Sample Collection & Analysis Sample Type : Plasma with citrate anticoagulant (pH 6.2-6.6) Critical Points :Avoid hemolysis (RBC contain high levels) Rapid platelet separation required pH and heat labile enzyme Clinical Significance Age Variations : Newborns have 2-3x higher levels than adults Gender Differences : Adult males show ¼ to ½ of total plasma levels from prostate Interference : Fluoride inhibits activity; oxalates and heparin reduce levels --- 2. Creatine Kinase (CK) Basic Function Primary Role : Energy metabolism through ATP breakdown Reaction : Creatine + ATP ⇌ Phosphocreatine + ADP Distribution : Cardiac muscle, skeletal muscle, brain Isoenzyme Profile CK-MM (M₂) → Skeletal & cardiac muscle ⟨Half-life: 15 hours⟩ CK-MB (MB) → Cardiac muscle exclusively ⟨Half-life: 12 hours⟩ CK-BB (B₂) → Brain tissue ⟨Half-life: 3 hours⟩ Clinical Applications Myocardial Infarction : CK-MB peaks 2 days post-attack, returns to normal by day 4 Muscle Disorders :Muscular dystrophy Polymyositis Skeletal muscle damage Neurological Conditions :Cerebral thrombosis Brain infarction Cerebral embolism Sample Requirements Sample Type : Serum only (anticoagulants inhibit activity) Storage : Protect from light (light-labile enzyme) Normal Variations : Males females (higher muscle mass) --- 3. γ-Glutamyl Transferase (GGT) Basic Function Primary Role : Amino acid transport and glutathione metabolism Distribution : Biliary ducts (liver), kidney, pancreas Clinical Applications Liver Disease Diagnosis :Proportional marker for liver damage Elevated in obstructive jaundice and hepatitis Combined with alkaline phosphatase and ALT for confirmation Alcohol Monitoring : Most Important Application Production proportional to alcohol consumption duration Sensitive indicator of chronic alcohol use Kidney Function : Elevated urinary GGT indicates renal damage Sample Collection Sample Type : Serum (citrate, oxalate, fluoride inhibit activity) Interference : Heparin causes turbidity affecting spectrophotometric analysis Factors Affecting Levels Gender : Males females Age : Newborns adults Drugs : Anticonvulsants, barbiturates, aminoglycosides increase levels Conditions : Gross obesity elevates GGT --- 4. Lactate Dehydrogenase (LDH) Basic Function Primary Role : Lactate ⇌ Pyruvate conversion Reaction : Lactate + NAD⁺ ⇌ Pyruvate + NADH + H⁺ Distribution : Kidney, heart, skeletal muscle, brain, liver, lungs Isoenzyme Profile LDH₁ (H₄) → Cardiac muscle ⟨17.5-28.3%⟩ • Myocardial infarction marker LDH₂ (H₃M) → Cardiac muscle ⟨30.4-36.4%⟩ • Cardiac damage indicator LDH₃ (H₂M₂) → Lungs ⟨19.4-24.2%⟩ • Pulmonary infarction marker LDH₄ (HM₃) → Kidney ⟨9.6-15.6%⟩ • Renal damage indicator LDH₅ (M₄) → Skeletal muscle, liver ⟨5.5-12.7%⟩ • Liver damage marker Clinical Applications Myocardial Infarction : "Flipped Pattern" : LDH₁ LDH₂ (normally LDH₂ LDH₁) Develops 24 hours post-infarction Persists 1-2 days then reverts to normal Organ-Specific Damage :Lung damage: Elevated LDH₃ Liver damage: Elevated LDH₅ General tissue damage indicator Sample Requirements Sample Type : Serum (oxalates inhibit activity) Storage : Avoid freezing (destroys isoenzymes) Interference : Avoid hemolysis (RBC contain significant LDH) --- 5. Aminotransferases (AST & ALT) Basic Function Primary Role : Amino group transfer between amino acids and keto acids Reversible catalysis : Essential for protein metabolism Distribution & Specificity AST (SGOT) → Heart, liver ⟨: 6-18 U/L : 7-21 U/L⟩ • Cardiac & hepatic damage ALT (SGPT) → Liver (primary) ⟨: 4-17 U/L : 6-24 U/L⟩ • Liver-specific marker Clinical Applications Liver Disease :Viral hepatitis: Remarkable increase in both enzymes ALT AST in liver inflammation (greater liver specificity) ALT used for blood bank screening (hepatitis detection) Cardiac Conditions : AST elevation in myocardial damage Other Applications : AST in pulmonary embolism Sample Collection Sample Type : Serum or plasma (no anticoagulant inhibition) Critical Point : Avoid hemolysisRBC contain 10-15x AST levels vs. serum RBC contain 5-8x ALT levels vs. serum --- 6. Amylase Basic Function Primary Role : Starch digestion (polysaccharides → mono/disaccharides) Sources : Salivary glands (salivary amylase), pancreas (pancreatic amylase) Normal Level : 50-250 U/L Clinical Applications Acute Pancreatitis : Primary diagnostic application Ectopic Production :Tumors in lungs, ovary, colon Glandular transformation in cancer Diabetic Ketoacidosis : Elevated levels Salivary Gland Disorders :Mumps, salivary stones Post-sur