41. All these aspects of metabolism can be represented in energy units. 42. He studied alcoholic fermentation and the chemistry of metabolism and digestion. 43. In human metabolism , bilirubin is a breakdown product of heme. 44. This reaction is embedded in the more general tryptophan metabolism pathway. 45. Warmer temperatures would actually increase their metabolism and shorten their lifespan. 46. This enzyme participates in pyruvate metabolism and glyoxylate and dicarboxylate metabolism. 47. This enzyme participates in pyruvate metabolism and glyoxylate and dicarboxylate metabolism . 48. This enzyme participates in beta-alanine metabolism and propanoate metabolism. 49. This enzyme participates in beta-alanine metabolism and propanoate metabolism . 50. This enzyme participates in tyrosine metabolism and benzoate degradation via hydroxylation.