Clinical Chemistry AACC Online Job Center
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Clinical Chemistry 24: 208-211, 1978;
This Article
Right arrow Full Text (PDF)
Right arrow Submit an electronic Letter to
the Editor about this paper
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Chapdelaine, P.
Right arrow Articles by Dube, J. Y.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Chapdelaine, P.
Right arrow Articles by Dube, J. Y.

Clinical Chemistry, Vol 24, 208-211, Copyright © 1978 by American Association for Clinical Chemistry

P-Nitrophenol-alpha-D-glucopyranoside as substrate for measurement of maltase activity in human semen

P Chapdelaine, RR Tremblay and JY Dube

Hitherto, seminal plasma maltase has been measured with maltose as substrate; this method is time consuming and lacks specificity. The use of a synthetic substrate, p-nitrophenol-alpha-D-glucopyranoside, allows accurate and rapid determination of this activity. When maltase is added to the incubation medium (the substrate and reduced glutathione in potassium phosphate buffer, pH 6.8), maintained at 37 degrees C, hydrolysis of the original substrate to p-nitrophenol goes at a constant rate during 4 h. Under optimal conditions of incubation, the Michaelis constant of the reaction, calculated by the Hanes method, was 2.92 +/- 0.84 (SD) X 10(-3) for six different semen samples. Isomaltase appeared to be absent from seminal plasma. The enzyme is stable to freezing and slow thawing and can be stored for at least 26 days at -80 degrees C. Its molecular weight is 259 000. Tris(hydroxymethyl)aminomethane (pH 6.8) exerts a noncompetitive inhibition on the enzyme activity. In 68 men 23 to 45 years old, whose semen analyses were normal, the seminal plasma maltase activity was 467 +/- 135 (SD) mU/g of protein. It was generally decreased in patients with infertility disorders.




HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1978 by the American Association for Clinical Chemistry.