M.Prasad NaiduMSc Medical Biochemistry, Ph.D,.

Possess multiple amino groups Putrescine, spermine & spermidine are

biologically imp Spermine & spermidine were detected in

human semen (sperm) hence the name

Precursors: Ornithine & SAM ( only the four carbon moiety but not CH3)

Ornithine decarboxylase splits off CO2 and produce Putrescine

Ornithine decarboxylase has the shortest half life ( 10 min) among the mammalian enzymes

It regulates polyamine synthesis Activators: corticosteroids, testosterone,

GH

Polyamine oxidase of liver peroxisomes oxidizes spermine to spermidine and then to putrescine

Spemidine and putrescine are excreted in urine in a conjugated form, as acetylated derivatives

Some amount of putrescine is also oxidized to NH3 and CO2

Basic in naturePossess multiple positive chargesHence they are readily associated with nucleic acids

Synthesis of DNA & RNA and proteins

Essential for cell growth & proliferation

Some enzymes are inhibited by polyamines ( protein kinase)

Stabilization of membrane structure (cell and cellular organelles)

The excretion of Polyamines is found to be elevated in almost all types of cancers

Eg: leukemias; carcinoma of lungs, bladder, kidney

Diagnostically putrescine is an ideal marker for cell proliferation

Spermidine is suitable for the assessment of cell destruction