In muscle tissue only (+)-lactic acid is found but in sour milk both (+)-lactic acid and (-)-lactic acid are present. This difference might be explained by the fact that the production of lactic acid in muscle tissue is catalyzed by biological catalysts or enzymes.

Question

Quizplus · Accepted Answer

In muscle tissue, the enzyme lactate dehydrogenase specifically catalyzes the formation of (+)-lactic acid (L-lactic acid) during anaerobic respiration. In contrast, sour milk contains both (+)-lactic acid and (-)-lactic acid (D-lactic acid) because the bacteria involved in fermentation can produce both forms, not being limited by the specificity of human enzymes.

In Muscle Tissue Only (+)-Lactic Acid Is Found but in Sour