... 1. Acid Phosphatase Basic Function - Primary Role : Hydrolysis of phosphate esters at acidic pH (5-6) - Location : Lysosomes (cytoplasmic enzyme) - Distribu
... 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 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-surgical complications Drug Interactions - Sphincter of Oddi Effects : Codeine, morphine cause spasm - Glucocorticoids : Dexamethasone, oral contraceptivesMechanism 1: Transient pancreatitis - Mechanism 2: Impaired liver clearance Urinary Considerations - Molecular Weight : 40,000-50,000 kD (easily filtered) - Amylase-Creatinine Clearance Ratio :Formula: (Urine amylase × Serum creatinine)/(Serum amylase × Urine creatinine) × 100 - Normal: 1-5% - 5%: Indicates organ damage --- 7. Lipase Basic Function - Primary Role : Triglyceride metabolism (sequential fatty acid removal) - Source : Pancreas (primary), small amounts in RBC and lymphocytes - Normal Level : 4-24 U/L Clinical Applications - Acute Pancreatitis : Primary diagnostic tool - Elevated 2-4 days post-damage - Advantage : Longer plasma half-life than amylase - Limitation : Cannot diagnose chronic pancreatitis (single source dependency) Sample Requirements - Sample Type : Serum only (avoid plasma with cellular components) - Critical Points :Avoid hemolysis - Prevent bacterial contamination - Avoid drugs causing sphincter spasm Interference Factors - Bacterial Contamination : Increases leukocyte lipase release - Drugs : Codeine, morphine (sphincter spasm) - Cellular Components : RBC and WBC contain lipase --- Summary of Key Clinical Applications ◆ Acid Phosphatase → Prostate cancer screening • Plasma (citrate) • Hemolysis, pH changes ◆ Creatine Kinase → Myocardial infarction • Serum • Light exposure ◆ GGT → Alcohol monitoring • Serum • Heparin turbidity ◆ LDH → Tissue damage (general) • Serum • Hemolysis, freezing ◆ AST/ALT → Liver disease • Serum/Plasma • Hemolysis ◆ Amylase → Acute pancreatitis • Serum/Plasma • Ca²⁺ chelation ◆ Lipase → Acute pancreatitis • Serum • Bacterial contamination This comprehensive guide provides the essential functions and clinical applications of all major tissue-specific enzymes used in clinical diagnostics.