ABSTRACT. Collapse of Mount Pinatubo's edifice during its explosive eruptions on June 15, 1991, created a 2.5-kilometer-wide caldera. By early September 1991, a lake began to form on the caldera floor, mainly by spring discharge from the walls of the caldera augmented by rainfall and surface runoff.igure 1. Progressive development of the Pinatubo caldera lake. A, Pinatubo caldera on August 1, 1991, before the caldera lake began to form (photographed from the northwest by T. Casadevall, USGS). B, Pinatubo caldera lake as seen on September 10, 1991 (photographed from the northwest by T. Pierson, USGS).
Enzymes are central to every biochemical process that occurs in the body. Most enzymes are proteins . There are exceptions, however. For example, there are catalytic ribonucleic acid (RNA) molecules called ribozymes that are involved in RNA processing, and, in 1994, the first DNA enzyme was engineered.
How Do Enzymes Work in the Human Body? Enzymes are proteins that allow certain chemical reactions to take place much quicker than the reactions would occur on their own. Enzymes function as catalysts, which means that they speed up the rate at which metabolic processes and reactions occur in living organisms. Usually, the processes or reactions are part of a cycle or pathway, with separate reactions at each step. Each step of a pathway or cycle usually requires a specific enzyme.