TY - JOUR
T1 - A Basic Mathematical Simulation of the Chemical Degradation of Ancient Collagen
AU - Collins, Matthew J.
AU - Riley, Michael S.
AU - Child, Angela M.
AU - Turner-Walker, Gordon
PY - 1995/3
Y1 - 1995/3
N2 - The diagenesis of ancient bone collagen appears bewildering in its variety. We have simulated collagen diagenesis using a simple conceptual model in which the degradation is controlled by two key processes: (i) depolymerization of collagen by chemical hydrolysis of peptide bonds; and (ii) dissolution (i.e. melting free) of those polypeptide fragments retained by fewer than a critical number of hydrogen bonds, biodeterioration being ignored. The model predicts that the curve describing weight loss is approximately sigmoidal in form, a pattern in accord with the sparse experimental data for non-mineralized collagen. The conclusion from studies of mineralized collagen is that the weight loss curve is exponential (i.e. a first-order reaction), but we argue that the experimental design of those studies was flawed. Other predictions of the model relating to the changing size distribution of residual fragments, N-termini, physical properties and significance of cross-linking are reported. Cross-linking appears to be a particularly significant phenomenon, which causes a marked tailing of the weight loss curve and thus the enhanced preservation of cross-linked, low collagen bone. The validity of applying this simple conceptual model to archaeological collagen is discussed.
AB - The diagenesis of ancient bone collagen appears bewildering in its variety. We have simulated collagen diagenesis using a simple conceptual model in which the degradation is controlled by two key processes: (i) depolymerization of collagen by chemical hydrolysis of peptide bonds; and (ii) dissolution (i.e. melting free) of those polypeptide fragments retained by fewer than a critical number of hydrogen bonds, biodeterioration being ignored. The model predicts that the curve describing weight loss is approximately sigmoidal in form, a pattern in accord with the sparse experimental data for non-mineralized collagen. The conclusion from studies of mineralized collagen is that the weight loss curve is exponential (i.e. a first-order reaction), but we argue that the experimental design of those studies was flawed. Other predictions of the model relating to the changing size distribution of residual fragments, N-termini, physical properties and significance of cross-linking are reported. Cross-linking appears to be a particularly significant phenomenon, which causes a marked tailing of the weight loss curve and thus the enhanced preservation of cross-linked, low collagen bone. The validity of applying this simple conceptual model to archaeological collagen is discussed.
KW - Archaeological bone
KW - Chemical degradation
KW - Diagenesis
KW - Enzymatic degradation
KW - Hydrolysis
KW - Mathematical simulation
KW - Mineralized collagen
KW - Tensile strength
UR - http://www.scopus.com/inward/record.url?scp=0000745015&partnerID=8YFLogxK
U2 - 10.1006/jasc.1995.0019
DO - 10.1006/jasc.1995.0019
M3 - Journal article
AN - SCOPUS:0000745015
SN - 0305-4403
VL - 22
SP - 175
EP - 183
JO - Journal of Archaeological Science
JF - Journal of Archaeological Science
IS - 2
ER -