PROBLEM TO BE SOLVED: To provide a proteoglycan having improved water retention in proteoglycan. SOLUTION: This is a salmon-derived proteoglycan that satisfies all of the following 1) to 3). 1) The ultimate viscosity is about 21.2 dL / g. 2) As an element, the carbon content is about 37% by weight, the sulfur content is about 6.2% by weight, and the nitrogen content is about 3.3% by weight. 3) The uronic acid content by the carbazole sulfate method is 40% by weight or more, and the protein content by the Lowry method is 4% by weight or less. [Selection diagram] Fig. 1【課題】プロテオグリカンにおいて、保水性が改善されたプロテオグリカンを提供する。【解決手段】以下の１）～３）を全て満たす鮭由来のプロテオグリカンである。１）極限粘度が約２１．２ｄＬ／ｇ。２）元素として炭素の含量が約３７重量％、硫黄の含量が約６．２重量％、窒素の含量が約３．３重量％。３）カルバゾール硫酸法によるウロン酸含量が４０重量％以上量、かつローリー法によるタンパク質含量が４重量％以下。【選択図】図１
