Book excerpt: Chemistry and Methods of Enzymes, Third Edition focuses on the processes, methodologies, and reactions in enzyme chemistry, as well as kinetics, nucleases, esterases, and carbohydrates. The publication first underscores the general properties of enzymes, including chemical nature, occurrence, numerical characterization of enzyme concentration, kinetics of enzyme reactions, preparation of commercial enzymes, purification and preservation of enzymes, relations of vitamins to enzymes, and zymogens and kinases. The text then takes a look at esterases and carbohydrates. Topics include pectin depolymerase, heparinase, xylanase, chitinase, dextranase, trehalase, nucleotide phosphatases, glucosulfatase, and gastric lipase. The manuscript examines nucleases, nuclein deaminases, amidases, proteolytic enzymes, and hydrases. Discussions focus on enolase, aconitase, peptidases as metalloproteins, glutaminases, aspartase, urease, adenosine deaminase, and nucleoside phosphorylase. The book also elaborates on iron and copper enzymes, dehydrogenases containing coenzymes I and II, and yellow enzymes. The text is a dependable source of data for chemists and researchers wanting to dig deeper into the chemistry and methods of enzymes.