During autopsy of a drowned body, the doctor notices greenish-black discoloration of the skin of the right iliac fossa region first. The enzyme predominantly responsible for initiating this discoloration is:
- A Catalase released from myocardium
- B H2S produced by bacterial action on hemoglobin ✓
- C Phospholipase released from lysosomes
- D Hyaluronidase from subcutaneous bacteria
Correct answer: B. H2S produced by bacterial action on hemoglobin
Explanation
Decomposition begins earliest in the right iliac fossa because the caecum, with its high bacterial load, lies just deep to that skin. Anaerobic gut bacteria (mainly clostridia and coliforms) produce hydrogen sulphide (H2S), which reacts with haemoglobin to form sulphhaemoglobin, giving the characteristic greenish-black discoloration. This is the first external sign of putrefaction and does not primarily depend on lysosomal enzymes or catalase.
Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.