All about Enzymes

Enzymes & Metabolism What is an enzyme? Proteins that serve as catalysts to speed up or slow down reactions, remain unchanged What is metabolism? Sum of all the chemical processes within living things What types of reactions are part of metabolism? Catabolism and Anabolism

The Basics Catabolism -”breakdown” of large molecules into smaller units to release energy ex= polysaccharide > monosaccharide, protein > Amino Acid Anabolism - "building up" organs and tissues, uses energy, ATP Activation energy-a jump start Cellular temperatures - Enzymes act as biological catalysts-

Biochemical pathways Processes in living orgs usually take place in steps THAT’S A LOT OF ENZYMES!!!!!!

http://www. lewport. wnyric http://www.lewport.wnyric.org/jwanamaker/animations/Enzyme%20activity.html

So, what are enzymes anyway? Proteins folded into a globular structure Substrate - the reactant/s that the enzyme binds with to speed up the reaction Active site - surface shape or cleft on the enzyme to which the substrate must fit like a lock and key Enzymes are Substrate Specific

Catalytic cycle- catabolism - “breakdown”

Catalytic cycle - anabolism >”build up”

How do enzymes speed up reaction rate? They lower the activation energy needed Most enzyme reaction rates are millions of times faster than those of comparable uncatalyzed reactions

Physical environment may also affect reaction rate Temperature pH Competitive inhibitors

Denaturation - major change in protein or nucleic acid structure by application of some external stress example - cooking an egg, egg whites become more solid, protein denatured, solubility lost

Biological Feedback How cells control their Chemical reactions Enzyme specificity Biochemical Pathways Several to many enzymes are placed side by side on membranes within cells, each enzyme completing one of the many steps to convert 1 substance into another. ("Assembly Line")

Biochemical Pathway - consist of a series of enzyme catalyzed chemical reactions. The product of each reaction in a pathway becomes the reactant of the next reaction in the pathway.