I. Definitions

Enzyme -- A protein that breaks down other chemicals

Phosphate -- A mineral.  Together with calcium, phosphate forms bone mineral crystals (hydroxyapatite)

Substrate -- A chemical broken down by an enzyme

Alkaline Phosphatase (ALP) -- One of many enzymes.  Releases phosphate from substrates.  Plentiful in cartilage, bone and liver

Pyridoxal 5'-phosphate (PLP) -- A form of vitamin B₆

Phosphoethanolamine (PEA) -- A chemical found in urine

Inorganic Pyrophosphate (PPi) -- A chemical that can block bone mineral crystal formation

Growth Plate -- The area of cartilage at either end of a long bone where growth occurs

Rickets -- Soft bones in infants or children from undermineralized skeletal tissue

Osteomalacia -- Soft bones in adults (they have fused growth plates)

Gene -- A DNA structure that encodes how a protein, including enzymes like alkaline phosphatase, will be made by cells

Mutation -- A defect in a gene

Craniosynostosis -- Fusion of skull growth plates

Cementum -- A coating on tooth roots that anchors teeth to the jaw

Osteoblast -- The ALP-rich cell that makes bone

Pseudofracture -- A slowly-forming incomplete fracture

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