This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Structure & Function of Proteins), Subject name: Biochemistry
[{'content': 'Which one of the following can be a homologous substitution for isoleucine in a protein sequence? \nSelect and explain. \nA. Methionine, B. Aspartic acid, C. Valine, D. Arginine', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. C. ValineHomologous substitutions are those which don't affect the function. Valine is an amino acid with aliphatic side chain and isoleucine also has aliphatic side chaina. Methionine is a Sulphur containing amino-acid and will not be a homologous substitution for isoleucineb. Aspartic acid has an acidic side chain and will not be a homologous substitution for isoleucinec. Valine has aliphatic side chain and will be a homologous substitution for isoleucined. Arginine has a basic side chain and will not be a homologous substitution for isoleucine", 'role': 'assistant'}]