Fig. 2.

Collagen type II extraction flow chart from cartilage tissues (the detailed protocol can be found here [131, 143]) and electrophoretic mobility of collagen type I and collagen type II (the detailed protocol can be found here [223]). Notes: As the same protocol is used to extract collagen type I [224], [225], [226], attention should be paid during dissection to remove all not cartilaginous tissues. Tissue to acetic acid / pepsin solution ratio: 1:1 g/l. Tissue to pepsin ratio: 10:1 w/w. High activity pepsin (e.g. 3200-4500 units per mg protein) is recommended. Sieve: approximately 1,000 μm in diameter. Filter mesh: 100 μm in diameter. Centrifugation details: 20 min, 8000 rpm, < 8 °C. After the second NaCl precipitation, dissolution is conducted in minimum amount of acetic acid in order to produce a high in concentration collagen type II solution. All experiments are conducted at 4-8 ºC to avoid collagen denaturation.