RT Book, Section A1 Goodman, Stephen I. A1 Saudubray, Jean-Marie A2 Rudolph, Colin D. A2 Rudolph, Abraham M. A2 Lister, George E. A2 First, Lewis R. A2 Gershon, Anne A. SR Print(0) ID 6724685 T1 Chapter 137. Disorders of Branched Chain Amino and Organic Acid Metabolism T2 Rudolph's Pediatrics, 22e YR 2011 FD 2011 PB The McGraw-Hill Companies PP New York, NY SN 978-0-07-149723-7 LK accesspediatrics.mhmedical.com/content.aspx?aid=6724685 RD 2024/03/28 AB The three essential branched chain aminoacids (BCAAs), leucine, isoleucine, and valine encompass about 25% of human protein. They are metabolized in mitochondria. The first two catabolic steps are common to the three BCAAs (Fig. 137-1). The first reaction, which occurs primarily in muscle, involves reversible transamination to 2-oxo (or keto) acids and is followed by oxidative decarboxylation to coenzyme A (CoA) derivatives by branched-chain oxo (or keto) acid dehydrogenase (BCKD). BCKD is similar in structure to pyruvate dehydrogenase, is also highly regulated by a kinase/phosphatase system and plays a key role in nitrogen metabolism.