**2. Results**

### *2.1. Collagen Is a Basic Component of the GSCM*

### 2.1.1. Amino Acid Analysis

According to the amino acid analysis, the content of hydroxyproline (Hyp) in the GSCM was 86.3 residues, proline (Pro)—91.3 residues per 1000 residues (Table 2). The Hyp percentage in the studied specimen was 10.13 weight %.

The specimen also contained a large amount (330 per 1000 residues) of glycine (Gly). The weight percentage of Gly was 22.18%. This finding is related to the fact that a molecule of collagen consists of a triple helix formed by three polypeptide helical strands, and each helical chain is formed by three-residue-long repeats, with glycine as one of the three residues. Thus, the primary structure of collagen is characterized by a large content of glycine. The high content of glutamic acid (Glu) in the specimen is explained by the presence of proline (Pro) since Pro is synthesized from glutamic acid.


**Table 2.** Amino acid composition of the *D. gigas* CM.

\* Percentage of amino acids to the mass of the test sample.
