The nature of the end products from the enzymic treatment of tropocollagen and collagen fibrils

Abstract

Treatment of a solution of rat tail tendon collagen in acetate buffer with a proteolytic enzyme (ficin) led to a monodispersed solution of rodlike particles whose dimensions were 12.6 A. in diameter and 2400 A. in length. Similar enzymic treatment of dispersions of steer tendon collagen fibrils resulted in a disaggregation of the fibrils to a solution of particles of essentially similar dimensions. The nature of the enzymic attack in relation to the structure of the substrate is discussed.

The Physical Characterization of Monomeric Tropocollagen*

“…Several physical parameters, including a partial specific volume of 0.655 and a molecular weight of Q VJince the important experiments of Boedtker and Doty (1956) which established the high asymmetry and approximate dimensions of native tropocollagen molecules in solution, a number of other physical investigations on these solutions have been reported. One of the factors that has plagued investigators has been the tendency of the acicular molecules to aggregate, particularly under certain conditions of ionic strength and in certain solvents (e.g., Barkin and Oneson, 1961;Rice et al, 1964). In studies in this laboratory over several years, most of the physical properties of different preparations have varied little, but the intrinsic viscosity of successive preparations has increased, due, we now believe, to increasingly effective prevention of proteolytic attack by contaminating proteases and microorganisms and of slow hydrolysis of labile bonds in acid solutions.…”

The purification and amino acid composition of human uterus collagens, rheumatoid-arthritis-nodule collagen and ox tendon collagen

“…It was also necessary to show that the cross-links of collagen were not broken, as occurs with certain other proteolytic enzymes (Barkin & Oneson, 1961;Highberger, 1961;Kiihn, Hannig & Hbrmann, 1961;Nishihara, 1962;Schmitt, 1963;Kiihn, Fietzek & Kiihn, 1963;Rubin, Pfahl, Speakman, Davison & Schmitt, 1963). The resultant collagen in these cases is soluble in acid buffers.…”

“…The hydroxylysine and lysine contents of preparations U2, U4 and P1 are intermediate between those of bone and tendon collagen. The high hydroxyproline content of preparations U2 and U4 iS of interest in view of the low shrinkage temperature of uterine collagen (Brown et al 1958). It had been thought that shrinkage temperature and hydroxyproline content were closely related.…”

“…As uterine collagen exhibits markedly different behaviour at different stages it was decided to study postmenopausal and puerperal uteri. After the menopause, the uterus decreases in weight and, although the collagen present never again undergoes the rapid changes induced by pregnancy, it still differs from non-uterine collagen in certain physical properties (Brown, Consden & Glynn, 1958). The wet weight of the uterus increases about 11-fold during pregnancy and decreases again during the puerperium, the period of time after parturition.…”