A 38-year-old woman with a history of chronic alcoholism and poor oral intake is admitted with complaints of fatigue, bone pain, and spontaneous bruising over her arms and legs. On examination, she has perifollicular hemorrhages, corkscrew hairs, and swollen, bleeding gums with some teeth already lost. Her serum albumin is 2.8 g/dL and hemoglobin is 8.5 g/dL. X-rays of the long bones show a characteristic 'scorbutic rosary' appearance. Which of the following biochemical consequences of her deficiency state directly explains the defective bone matrix formation observed on imaging?