Meat tenderness: immunofluorescent localisation of the isomorphic forms of collagen in bovine muscles of varying texture

The three isomorphic forms of collagen present in muscle have been located by indirect immunofluorescence using collagen type specific antibodies. Type I collagen was located in the epimysium and perimysium, type III primarily in the perimysium as fine lace‐like fibres, and type V virtually confined to the endomysium. Increased proportions of type III collagen appeared to be present in the perimysium of the tougher muscles M. carpi radialis, and M. sternomandibularis compared to M. semitendinosus and M. longissimus dorsi. This increased proportion of type III was confirmed by analysis of the cyanogen bromide peptides. The relationship of the increased proportion of type III collagen to increased toughness, if any, remains to be elucidated.