Clinically Significant Enzymes

• What is the optimum pH for alkaline phosphatase?

  9-10 pH
• This enzyme catalyzes the hydrolysis of various phosphoesters at an alkaline pH?

  Alkaline phosphatase
• What is the activator of ALP?

  Magnesium
• What are the 6 isoenzymes of ALP?

  Liver, Bone, Placental, Intestinal, Regan, Nagao
• What isoenzyme of ALP is the most anodal? How about least anodal?

  Most anodal isoenzyme of ALP: Liver ALP Least anodal isoenzyme of ALP: Intestinal ALP
• What isoenzyme of ALP is heat stable? How about heat labile?

  Heat stable isoenzyme of ALP: Placental ALP Heat labile isoenzyme of ALP: Bone ALP
• What are the associated disorders with the isoenzyme Regan ALP?

  Lung, breast, and gynecological cancers
• What are the associated disorders with the isoenzyme Nagao ALP?

  adenocarcinoma of pancreas, bile duct and pleural cancer
• What is the reference method for Alkaline phosphatase determination?

  Bower's and McComb
• In bower's and mccomb method for ALP what is the wavelength used?

  405 nm
• What is the substrate used in Bower's and McComb?

  P-nitrophenyl phosphate
• ALP interferences include?

  Hemolysis = ALP is 6x in RBC

  3-10% increase upon standing in RT or 4C

  Diet - 25% higher in High-Fat meal
• What inhibits Nagao ALP? How about regan ALP?

  NAgao: Phenylalanine and L-leucine

  Regan: Phenylalanine
• What substance inhibits intestinal and placental ALP?

  PHENYL ALANINE
• In billiary obstruction how much is ALP increased?

  3-10x
• What inherited disorder causes a deficiency or absence of ALP enzyme?

  Hypophosphatasia
• Normal value of ALP for male and female?

  Male: 53-128 U/L

  Female: 42-98 U/L
• This enzyme catalyzes the same reactions as ALP but in an acidic pH?

  Acid Phosphatase
• What pH is ACP active?

  pH 5.0
• Major tissue source for ACP?

  Prostate
• What is the most specific substrate for ACP determination?

  Thymolphthalein monophosphate (Quantitative Endpoint)
• What substrate is used for continuous monitoring assays for ACP?


  ALPHA-naphthyl monophosphate
• What substance inhibits Prostate ACP?

  L-tartrate
• What are the substances that inhibit RBC ACP?

  2% Formaldehyde and 0.001M Cupric sulfate
• What isoform of ACP is used as a tumor marker for prostatic cancer?

  P2-PSA
• How is ACP preserved?

  ACIDIFICATION
• What is the normal value of ACP for male and females?

  MALE: 2.5-11 U/L

  FEMALE: 0.3-9.2 U/L
• This enzyme is involved in transfer of amino group between aspartate and alpha keto acids with the formation of oxaloacetate and glutamate?

  Aspartate aminotransferase (AST) or Serum Glutamic Oxaloacetate Transaminase (SGOT)
• What is measured in the AST/SGOT assay?

  Decrease in NADH concentration
• What is the relationship between concentration of NADH and AST/SGOT activity?

  It is proportional
• What is the coenzyme for an AST/SGOT reaction?

  Pyridoxal phosphate (P.5'.P)
• What is the source of error for AST/SGOT determination?

  Hemolysis - 10x increase
• What is the principle used in AST/SGOT determination?

  Karmen (pH 7.3-7.8)
• What is the analyte analysed in AST/SGOT determination using KARMEN?

  Malate
• What are the Isoenzymes of AST/SGOT?

  Cytoplasm and Mitochondria
• In AMI, when does AST/SGOT rise? Peak? Normalizes?

  Rise: 6-8 hours

  Peak: 24 hours

  Normalizes: within 5 days
• What disorder do we see an 8x rise in AST/SGOT concentration?

  Dermatomyositis
• This enzyme catalyzes the transfer of an amino group from alanine to alpha-ketoglutarate with formation of pyruvate and glutamate?

  Alanine aminotransferase (ALT) or Serum Glutamic Oxaloacetic Transaminase (SGPT)
• This enzyme is more liver specific compared to AST?

  ALT/SGPT
• What is the coenzyme for ALT?

  Pyridoxal phosphate (P.5'.P)