# Vitamin B2 (Riboflavin)

**Summary**

Vitamin B2 (Riboflavin) is a water-soluble vitamin which serves an important role as a precursor for the flavin coenzymes, including flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These flavins serve as cofactors in a number of redox reactions. One of the major enzymes requiring flavins (FAD+) as a cofactor is succinate dehydrogenase, which plays major roles in the Citric Acid Cycle and electron transport chain. In patients with riboflavin deficiency, cheilosis and corneal vascularization are characteristic findings.

**Key Points**

- **Vitamin B2 (Riboflavin)**
  - Component of **flavins (FAD**, **FMN)**
    - used in electron transport chain and as cofactors in **redox reactions:**
      - **Succinate dehydrogenase**
        - Converts succinate to fumarate in TCA cycle
- Deficiency
  - **Cheilosis**
    - inflammation of lips; scaling and fissures at the corners of the mouth
    - Also glossitis and stomatitis
  - **Corneal vascularization**

Find Riboflavin and other [Vitamins](/content/browse#playlist-2700/index.html) among Pixorize's visual mnemonics for the USMLE Step 1 and NBME shelf exams.