Enzyme cytochemistry

Author: Nat Pernick, M.D. (see Authors page)

Revised: 30 September 2015, last major update July 2013

Copyright: (c) 2003-2015,, Inc.

PubMed Search: Enzyme cytochemistry[title]
  • Detects enzymatic activity in cytoplasm
  • Advantage over immunocytochemistry is determination of enzyme's intracellular localization and intensity of catalytic activity (for research purposes)
  • Flow cytometry and immunocytochemistry are often preferred to determine presence of enzyme molecule (but not catalytic activity or localization)
  • Enzyme product unites with coupler, which produces localized color at site of enzyme activity
  • Fresh smears are preferred, especially for myeloperoxidase; if not possible, store unstained slides away from light
  • Simultaneous capture: reagent in incubation medium combines with reaction product (example: diazo method for alkaline phosphatase)
  • Post-incubation coupling: insoluble reaction product is coupled with a colored or opaque substance (example: Rutenburg and Seligman method for acid phosphatase)
  • Self-colored substrate reaction: water-soluble dye is made insoluble when enzyme removes a hydrophilic group, leading to colored precipitate at site of enzyme activity
  • Intramolecular rearrangement: produces a colored insoluble precipitate at sites of enzyme activity of an otherwise colorless substrate (University of Iowa)
Uses by Pathologists
  • Used for these enzymes: acid phosphatase, alkaline phosphatase, myeloperoxidase, Sudan black B, nonspecific esterase
  • Also: acetyl cholinesterase, adenosine triphosphate, adenylate cyclate, catalase, cytochrome oxidase, 5' nucleotidase, nucleoside diphosphatase, succinic dehydrogenase and thiamine pyrophosphatase
Micro Images

AML-M2 (left), AML-M1 (right) show myeloperoxidase staining
(AFIP Third Series, Volume 9)

AML-M1: Sudan black B positive granules

AML-M0: myeloblasts are
negative for myeloperoxidase

AML-M4: non-specific esterase

AML-M4: lysozyme

AML-M4: chloroacetate esterase
and nonspecific esterase