<prompt> Number of isoenzymes in LDH enzyme -1345  <response>: D 5 65 Harper 29th LDH has 5 isoenzymes while CPK has three. LDH is an oligomeric tetrameric enzyme made up of four polypeptide. Two types of subunits namely M for muscle is basic and H for heart is acidic. LDHi has more positive charge and fastest in electrophoretic mobility while LDHS is slowest. LDH5 has low Km high affinity while LDH1 has high Km low affinity for pyruvate. Normal CSF LDH is 5 to 40 UL. Similar to AST Aspartate transaminase. Increase of CSF LDH observed in abscess, cerebral haemorrhage infarction and metastatic carcinoma. Increase of LDH4 isoenzyme of CSF has been reported in tubercular meningitis. Normal serum LDH activity ranges from 60 to 250 IUL 120 - 500 units mL Behavior in Acute MI In acute MI, serum activity rises within 12 to 24 hours attains peak at 48 hours 2 to 4 days reaching about 1000 IUL and then return gradually to normal from 8th to 14th day. The predominant isoenzyme of LDH in cardiac muscle is LDH-1 in Liver - LDH-5 Albumin helps in distinguishing an acute liver disease from chronic liver disease. 