Complex sentence: In response to extremes of temperature plants can produce various proteins that protect them from the damaging effects of ice formation and falling rates of enzyme catalysis at low temperatures and enzyme denaturation and increased photorespiration at high temperatures.
Split into simpler sentences: In response to extremes of temperature plants can produce various proteins. These protect them from the damaging effects of ice formation and falling rates of enzyme catalysis at low temperatures, and from enzyme denaturation and increased photorespiration at high temperatures.