丙酮酸脱氢酶

• 一(one; horizontal stroke on top)RADICAL
• 内(inside; within)ASSOCIATIVE

The third stem Bing carries fire blazing from inside outward.

• 酉(wine vessel; ferment)RADICAL
• 夋(slow manner; leisurely pace)PHONETIC

Fermenting alcohol produces sourness, which is exactly the character for sour.

• ⺼(flesh; body)RADICAL
• 兌(exchange; remove)PHONO-SEMANTIC

The body escapes from bonds through exchange to gain freedom.