This page uses JavaScript to simulate the pulse-chase labeling kinetics of the total pools of intermediates **B**, **C** and **D** in the compartmentalized metabolic scheme shown above, where the pools exist as metabolically active (met) and metabolically inactive, storage (stor) pools. **The JavaScript language is supported by Netscape Navigator and Microsoft Internet Explorer 3.0 or above**. If you are using a JavaScript-compatible browser, try varying the pool sizes and fluxes to determine how this influences the labeling patterns. Note than when the rate of synthesis exceeds the rate of utilization, the pool will expand with time. When the rate of utilization exceeds the rate of synthesis, the pool will deplete with time. *If a pool becomes zero during the time-course, the simulation will terminate before completion!*

** Starting values [values should not exceed 6 characters in length]:**

Enter A1:

Enter A2:

Enter B1:

Enter B2: ^{-1}))

Enter B3: ^{-1}.gfw^{-1}))

Enter B4: ^{-1}.gfw^{-1}))

Enter B5:

Enter B6: ^{-1}))

Enter B7: ^{-1}.gfw^{-1}))

Enter B8: ^{-1}.gfw^{-1}))

Enter C1:

Enter C2: ^{-1}))

Enter C3: ^{-1}.gfw^{-1}))

Enter C4: ^{-1}.gfw^{-1}))

Enter C5:

Enter C6: ^{-1}))

Enter C7: ^{-1}.gfw^{-1}))

Enter C8: ^{-1}.gfw^{-1}))

Enter D1:

Enter D2: ^{-1}))

Enter D3: ^{-1}.gfw^{-1}))

Enter D4: ^{-1}.gfw^{-1}))

Enter D5:

Enter D6: ^{-1}))

Enter D7: ^{-1}.gfw^{-1}))

Enter D8: ^{-1}.gfw^{-1}))

Enter time scale of the labeling simulation:

Enter time at which chase begins:

To disable the chase function, enter a "time at which chase begins" which is greater than the "time scale of the labeling simulation". After entering starting values (inputs), click the **Calculate** button. Simulated values will then be displayed in the text boxes below. The **Calculate** button can be reused repetitively after modifying input values.

** Computed time-courses of isotope abundance (atom %) and pool size (nmol.gfw ^{-1}):**

Note that the pool sizes shown in the text boxes above represent the sum of the "metabolic" and "storage" pools of B, C and D (i.e. B2 + B6, C2 + C6, and D2 + D6, respectively). The isotope abundances represent the average isotope abundances of the "metabolic" and "storage" pools of B, C and D (i.e. ((B1 * B2) + (B5 * B6))/(B2 + B6), ((C1 * C2) + (C5 * C6))/(C2 + C6) and ((D1 * D2) + (D5 * D6))/(D2 + D6), respectively). With certain browsers (e.g. Internet Explorer 3.0), the values displayed in the text boxes above are double-precision floating-point (e.g. 0.019995 may be displayed as 1.9995E-02). Thus, it may be necessary to use your mouse to highlight certain text boxes to view the full double-precision floating-point notations for values of less than 0.1. Errors resulting in script termination will occur when inputs are entered as text rather than as numerical values. Upon encountering such errors it may be necessary to "Refresh" the page.