# DBT JRF 2022 — Question 12

Exam: DBT JRF 2022 · Section: B · Topic: Biochemistry › Post-Translational Modifications · Difficulty: Medium

## Question

How many different kinds of post translational modifications are present in this peptide? ![figure](https://res.cloudinary.com/dxil5euku/image/upload/v1779453121/pyq/6a104cb5920734408bc0c6d8/DBTJRF22-IMGB12.png)

## Options

- **A.** One
- **B.** Two
- **C.** Four
- **D.** Nine

## Answer

Option B

## Explanation

Post-translational modifications (PTMs) in the peptide ![figure](https://res.cloudinary.com/dxil5euku/image/upload/v1779453121/pyq/6a104cb5920734408bc0c6d8/DBTJRF22-IMGB12.png) : From the structural image, the peptide contains two TYPES of post-translational modifications. Common PTMs visible in structural representations: • Phosphorylation (on Ser, Thr, Tyr: addition of –PO₃²⁻) • Glycosylation (addition of sugar moieties) • Acetylation (addition of –COCH₃) • Ubiquitination (addition of ubiquitin chain) • Hydroxylation (addition of –OH) The question asks about distinct KINDS of modifications; the answer is two types of modifications are visible in this peptide. Answer: Two types of PTMs (Option 2).

Source: https://mypyqbuddy.com/questions/how-many-different-kinds-of-post-translational-modifications-6a104cd5920734408bc0c71b