**Core Concept**
The analysis of protein antigens involves the breakdown of these complex molecules into smaller peptides that can be recognized by the immune system. This process is crucial for understanding the immune response to various pathogens and allergens.

**Why the Correct Answer is Right**
The correct method for analyzing protein antigens is through the use of enzymes that cleave the peptide bonds between amino acids. **Trypsin** and **Chymotrypsin** are two commonly used enzymes for this purpose. These enzymes cleave the peptide bonds at specific sites, resulting in a mixture of peptides that can be further analyzed using techniques such as mass spectrometry or Western blotting.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the type of enzyme used for protein antigen analysis. While **pepsin** is an enzyme that breaks down proteins, it is not typically used for the analysis of protein antigens.
**Option B:** This option is incorrect because **lysosomal enzymes** are involved in the breakdown of cellular components, but they are not typically used for the analysis of protein antigens.
**Option C:** This option is incorrect because **ribonucleases** are enzymes that break down RNA, not protein antigens.

**Clinical Pearl / High-Yield Fact**
When analyzing protein antigens, it is essential to consider the specific enzymes used for cleavage, as this can affect the resulting peptide mixture and the subsequent analysis.

**Correct Answer:** D. Proteolytic enzymes (such as trypsin and chymotrypsin).