Inhibitor Profiles of Alkaline Phosphatases in Bovine Preattachment Embryos and Adult Tissues

Abstract

The alkaline phosphatases are a small family of isozymes. Bovine preattachment embryos transcribe mRNA for two tissue-specific alkaline phosphatases (TSAP2 and TSAP3) beginning at the 4- and 8-cell stages. Whereas no mRNA has been detected in oocytes, there is maternally inherited alkaline phosphatase activity. It is not known which isozyme(s) is responsible for the maternal activity or when TSAP2 and TSAP3 form functional protein. No antibodies are available that recognize the relevant bovine alkaline phosphatases. Therefore, sensitivity to heat and chemical inhibition was used to separate the different isozymes. By screening tissues, it was determined that the bovine tissue-nonspecific alkaline phosphatase (TNAP) is inactivated by low temperatures (65C) and low concentrations of levamisole (<1 mM), whereas bovine tissue-specific isozymes require higher temperatures (90C) and levamisole concentrations (>5 mM). Inhibition by L-homoarginine and L-phenylalanine was less informative. Cumulus cells transcribe two isozymes and the pattern of inhibition suggested heterodimer formation. Inhibition of alkaline phosphatase in bovine embryos before the 8-cell stage indicated the presence of only TNAP. At the 16-cell stage the pattern was consistent with TNAP plus TSAP2 or -3 activity, and in morulae and blastocysts the pattern indicated that the maternal TNAP is fully supplanted by TSAP2 or TSAP3.

Immobilization of alkaline phosphatase on microporous nanofibrous fibrin scaffolds for bone tissue engineering

“…These results are consistent with previous studies showing that levamisole inhibits β-glycerophosphate-induced mineralization [5,7,21,22]. However, in our study, levamisole only partially inhibited ALP-induced mineralization, most likely because it was less effective in inhibiting intestinal ALP [23–25], which we used in this study. Foscarnet, a competitive inhibitor of sodium dependent phosphate cotransporters, also inhibited ALP-induced mineralization, consistent with previous reports that foscarnet can inhibit both β-glycerophosphate-induced and NaH 2 PO 4 -induced mineralization [5,26].…”

Identification of thiamine monophosphate hydrolyzing enzymes in chicken liver

“…Харак-терным свойством ЩФ является высокая чув-ствительность к левамизолу (декарису) -проти-воглистному препарату, который стимулирует н-холинорецепторы нервно-мышечных синап-сов гельминтов, вызывая тем самым спастиче-ский паралич их мускулатуры [18]. Для несколь-ких видов млекопитающих было показано, что активность тканенеспецифичных изоформ ЩФ (ТНЩФ) практически полностью подавляется при концентрациях левамизола < 1 мМ [19][20][21][22]; тканеспецифичные ЩФ менее чувствительны к действию ингибитора (I 50 для разных изоэнзи-мов колеблется в диапазоне 1,1-23,7 мМ [20][21][22]). В экспериментах на мышах установлено [6], что при рН 8,5 левамизол (в концентрации 2,5 мМ) ингибирует TMPазную активность гомогенатов почек на 94, печени -на 86, спинного мозга -на 83, сердца -на 69%.…”

Alkaline phosphatase activity in bovine oocytes and preimplantation embryos as affected by removal of the zona pellucida and culture medium constituents

“…In bovine embryos, TNAP transcripts were not detected until expansion and hatching of the blastoceole. Inhibition profiles of AP activity indicate that oocytes through eight-to 16-cell embryos express TNAP (McDougall et al 2002). However, by the 16-cell stage, AP activity is likely to be that of TNAP and TSAP2 or TSAP3.…”