Related Experiment Video
Updated: Aug 3, 2026

Preparation of Quality Inositol Pyrophosphates
Published on: September 3, 2011
Adenosine diphosphate ribose pyrophosphohydrolase in human skin
1Department of Dermatology, Chonnam University Medical School and Chonnam University Hospital, Kwang-Ju, Chonnam, Korea.
Abstract:
Adenosine diphosphate ribose (ADPR) pyrophosphohydrolase (ADPR-PPase), which catalyzes the hydrolysis of ADPR to yield adenosine monophosphate (AMP) and ribose-5'-phosphate, was assayed in human penile foreskin. Since ADPR is formed from nicotinamide adenine dinucleotide (NAD) by NAD glycohydrolase (NADase), NADase was also assayed in human skin. The skin tissue obtained by circumcision was separated into three layers; epidermis of the outer prepuce, epidermis of the inner prepuce, and dermis. ADPR-PPase was found to be present in all of the three layers with nearly equal activity. NADase was also present in the epidermis of both the outer and inner prepuce, being about two times higher in the latter, but no activity was found in the dermis. When expressed in units of the same specific activity; i.e., micromoles product formed per hour per mg protein, the ADPR-PPase of human skin had two to five times greater activity than did NADase. The ADPR-PPase of human skin was activated by Mg(+2), but inhibited by AMP and ATP. These results suggest that the breakdown of NAD occurs in human skin via ADPR to AMP and ribose-5'-phosphate by sequential action of NADase and ADPR-PPase.
Related Concept Videos
Hydrolysis of ATP
If one phosphate group is removed, a molecule of ADP—adenosine diphosphate—remains, along with inorganic phosphate. ADP can be further hydrolyzed to AMP—adenosine monophosphate—by the removal of a second...
Phosphorylation
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
Hydrolysis of ATP
If one phosphate group is removed, a molecule of ADP—adenosine diphosphate—remains, along with inorganic phosphate. ADP can be further hydrolyzed to AMP—adenosine monophosphate—by the removal of a second...
Protein Kinases and Phosphatases
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Role of Skin in Vitamin D Synthesis
The solar UV B rays (290-315 nm) are absorbed by the skin, and 7-dehydrocholesterol (provitamin D3) photolyzes it to previtamin D3, which undergoes a rapid transformation to vitamin D3(cholecalciferol).

